Why Do We Resist Fact-Checking?

The strange psychology behind when and why we ignore the facts.

It’s probably fair to say that we live in an era in which fact-checking would seem to be of paramount importance. Especially with the onset of the COVID-19 pandemic, but even before that, flat-out incorrect information spreads like fire throughout the internet and social media. In recent months, however, we’ve heard a lot about how fact-checking “doesn’t work.” 

So if fact-checking doesn’t work, should we stop spending so much time doing it? Not so fast. Whether or not fact-checking works in particular instances is actually quite nuanced. So when and how does fact-checking work? And what are the psychological drivers that lead people to resist it? 

For starters, it’s important to state one thing: fact-checking is still important, even if it doesn’t work in every instance. Fact-checking is both often very effective and necessary. Political fact-checking is also a phenomenon that supports democracy. Fact-checking has grown tremendously in the past 10 to 15 years, in part because there is a real appetite for it and people who depend upon it. Indeed, for the vast majority of people, fact-checking will work the majority of the time on the majority of topics. 

Mega Pixel/Shutterstock
Source: Mega Pixel/Shutterstock

There is a crucial caveat to this though—very vocal people on contested political issues (even ones that have clear factual answers like climate change) are not likely to respond to fact-checking on those issues. What’s more, because they are so vocal, it can seem like there are more of them than there actually are. In these cases, human cognition does not filter out emotions before looking at information and so even fact-checks may not be particularly persuasive on their own.

But that still doesn’t mean fact-checks serve no purpose in these cases, because they may still be effective as part of a multi-faceted intervention. People are most resistant when something comes up that challenges their world view, and since there isn’t a large study of the effects of fact-checking on everyone in the world, it’s hard to say that it “doesn’t work” even if we still hear a lot of misinformation circulating.

There are still things we can do to make fact-checking more effective. One is to share sources of disagreement that generally agree with people’s worldview overall (e.g. getting a Republican to refute an idea to a Republican rather than a Democrat). It also seems that graphical information, in the form of charts and other data visualization techniques, can be helpful.

Importantly, providing an alternative narrative rather than just a refutation on its own can be particularly salient. There are not a ton of data on the efficacy of real-time fact checks but it’s reasonable to think they’re still useful—after all, repeating misinformation can make it stronger so intervening before too much of that happens might help to reduce it.

Other effective methods include: aiming for the middle rather than people at the extremes, who are less likely to be swayed; and fact-checking that says things like “if you believe this, you are right” is more likely to be effective because people love to be told they are right—so including that actual phrasing can be motivating. 

There are major challenges to truth and facts in our world right now. But just because we are faced with resistance to facts does not mean we should essentially abandon them altogether. Better understanding the psychology that makes people cling to incorrect notions can help us build more effective multi-faceted strategies that include an understanding and appreciation of the importance of facts. 

Warp Speed for a COVID Vaccine

Why It is Possible to Develop a COVID-9 More Quickly

A concerted effort is now underway to develop a vaccine against the virus that causes COVID-19. That virus is called SARS-CoV-2 and it is a member of a family of viruses called coronaviruses that range in the severity of the diseases they cause from mild cold symptoms to severe respiratory distress, organ failure, and death. Nearly everyone in the world wants to see the pandemic end, although a few misled people still insist that it is a hoax cooked up by people who want to benefit financially and/or politically from a vaccine.

          The U.S. federal government is putting billions of dollars behind what it calls “Operation Warp Speed” to develop a vaccine more quickly than the decades it traditionally has taken to develop a new vaccine. We think that the phrase “warp speed” is unfortunate in this case because it reduces a very labor-intensive scientific process to something akin to science fiction (most people know about warp speed from the television show “Star Trek). Nevertheless, it is important to understand that there are several good reasons why a vaccine against SARS-CoV-2 could be developed more quickly than vaccines in the past. Here are three of them:

1.          Genomic sequencing is much faster than in the past: The first step in developing a vaccine is to know the genetic structure of the virus it is directed against. All human and other mammalian cells use double-stranded DNA as their genetic building blocks, but many viruses, like coronaviruses, use single-stranded RNA instead. Viral RNA enters the host human cell and commandeers its protein-making machinery, directing the human cell to make proteins that allow the virus to make many copies of itself. Like DNA, these instructions in the RNA molecule are written in a code comprised of bases strung together in a chain. By getting the sequence of those bases, a process known as genomic sequencing, scientists immediately know what some of the targets are for a potential vaccine. In the case of SARS-CoV-2, the whole genomic sequence of its RNA was completed in just three days back in January 2020. The ability to do this kind of rapid sequencing is only a few decades old and it gives scientists trying to develop a new vaccine an incredible head start.

Coronaviruses, like the one that causes COVID-19, have as their genetic molecule a single strand of RNA, which enters the host cell and captures its protein-making machinery (image: Shutterstock).

2.          The structure of other coronaviruses was already known. SARS-CoV-2 is a member of the virus family called coronaviruses, which includes two other viruses that cause the very serious illnesses called MERS and SARS. Coronaviruses got their name from the protein spikes that protrude from the viral surface, resembling a crown, the Latin word for which is “corona.” The coronavirus that causes SARS emerged in 2002 and the one that causes MERS in 2012, so scientists have known a great deal about them for almost two decades.  SARS-CoV-2 shares many structural similarities to those other potentially lethal coronaviruses, including the spike protein. Most of the vaccines now in development against SARS-CoV-2 target that spike protein.

The spikes on the surface of coronaviruses give the virus family its name and are a prime target for vaccines.

3.          Thousands of scientists around the world are working to develop the COVID-19 vaccine.  Many laboratories decided to focus attention on developing a COVID-19 vaccine almost as soon as the virus had been sequenced. Some dropped whatever else they were doing to join this effort.

What Will It Take?

Right now, there are around 300 anti-COVID-19 vaccine candidates in various stages of development and about three dozen already in human trials. Several have entered the third phase of new medication testing in which at least 30,000 people will randomly receive either a candidate vaccine or a placebo. The FDA has stated that in order for it to approve one of these vaccines, it must be 50% effective. That means, for example, if you vaccinate 100 people, only a maximum of 50% will get infected and that number must be statistically significantly lower than the number who get infected in the placebo group.

Effectiveness of only 50% may sound small. Shouldn’t we want a vaccine that is 100% effective. There are at least three good reasons to pick a level like 50%. First, it is possible the people who get the real vaccine (as opposed to placebo) and who do get infected may have less serious symptoms than people who get placebo and are infected.  That is the case with the influenza vaccine. Second, what we are after in any vaccination program is to establish “herd” or “community” immunity. That’s the point at which enough people are immune to the virus that it no longer can find enough people to infect and peters out on its own. Third, it just may not be practical to find a vaccine in short enough a timeframe that has a higher rate of effectiveness.

         Going back to the concept of herd or community immunity, Allison Aubrey of NPR did a little math for us. She begins by assuming we need between 60 and 70% of the population to be immune in order to establish community immunity, although some have estimated that even lower percentages may be sufficient. Then “if 20% of the U.S. population ends up getting exposed to the virus and developing an infection before we have a vaccine (as is estimated to be the level of immunity in the New York City metro area right now), then we would still need an additional 40% of the population to gain protection via a vaccine. And in order to get 40% of a population immune through vaccination — if you have a vaccine with 50% efficacy — ‘you’re going to have to vaccinate 80% of the population,’ says Carlos del Rio, an infectious disease expert at Emory University.’”

COVID Vaccine Hesitancy

          One would like to believe that everyone wants the vaccine in order to end this pandemic that has so changed and adversely affected our lives. But surveys have showed a range of between one third and one half of the population that say they would not be vaccinated when the vaccine becomes available. Some of the reasons for this reluctance are absurd, like believing the virus is a hoax or that Bill Gates is putting microchips in the vaccine in order to control peoples’ minds.

          But in our experience the major reason some people fear the vaccine is precisely the reason we have written this commentary—they feel it is being rushed into production without adequate safety assessment. Some even go further to assert they cannot trust the government’s leaders or its agencies to be transparent about whether a vaccine against COVID-19 is in fact safe. Both of these objections are understandable, so we will address them in turn.

          How do we know if a vaccine is safe? Remember that the large phase III clinical trials of any medication under development must involve something to which the active medication being tested is compared, in the case of putative COVID-19 vaccines that is a placebo, a shot containing only saltwater. They must also be doubled blinded, meaning that neither the researchers nor study participants know who has received active vaccine or placebo. Finally, they must involve large numbers of participants, in this case at least 30,000. During these trials, there are ongoing assessments of safety; that is, researchers ask participants a variety of questions and perform multiple tests to see whether any adverse side effects have occurred. They are unbiased in doing this because they don’t know who has received real vaccine and who has received placebo. Fairly uncommon safety problems can be uncovered because of the large number of subjects involved. If a serious side effect occurs in one out of 30,000 people, it would be a rate of 0.0033 percent. Of course, that doesn’t mean that such a rare event will crop up in the few months that these phase III trials will last, but a surveillance system will continue to scrutinize for rare adverse side effects even after a vaccine is ultimately approved.

          There are a few other things to know about vaccine safety. It is true that there have been some serious problems that arose with vaccines after approval in the past. In 1955 due to a flaw in the manufacturing process, some people received live polio virus in a vaccine that was supposed to only contain attenuated non-infectious virus. The result was 51 cases of permanent paralysis and five deaths. This kind of tragedy has not happened in the subsequent 65 years of vaccinations and is highly unlikely to occur today.

          More recently, in 1976 the swine flu vaccine was blamed for causing rare cases of a nervous system disorder called Guillain-Barre syndrome (GBS). In fact, the rate was one more case per 100,000 people who were vaccinated than occurs by chance. The 2009 H1N1 flu vaccine was at first said to cause rare cases of a sleep disorder called narcolepsy in some countries; subsequent studies failed to substantiate that claim in the U.S. and several other countries.

          Despite these rare, and in some cases controversial, safety issues, most vaccine-related adverse effects show up early after receiving a vaccination, so even a relatively short-term study would be expected to detect most safety issues. A recent review of all safety-related issues that have cropped up between 1996 and 2015 in already marketed vaccines “found that vaccines were remarkably safe.”

          The politics of anti-COVID-19 vaccine development are of course harder to assess. There is no question that the current administration wants a vaccine approved as soon as possible and some have claimed that it is pressuring researchers and drug companies to rush one into production without adequate testing. The head of the federal COVID-19 vaccine program, Moncef Slaoui, has said he would quit if he is pressured to act prematurely. The CEO’s of nine pharmaceutical companies involved in the race to develop a COVID-19 vaccine issued a letter stating they would not sacrifice safety in the process.

Data Safety and Monitoring Board

One of the farthest along phase III clinical trials of a vaccine—the one being developed jointly by the University of Oxford and drug company AstraZeneca—was halted in September 2020 because one woman developed an inflammation of the spinal cord, believed to be the rare disorder called transverse myelitis. At the time of this writing she was recovering and anticipating hospital discharge. The trial was later restarted in the UK but not in the US as of September 14, 2020.

          The evaluation of an adverse side effect like this in a clinical trial usually falls to something called a data safety and monitoring board (DSMB). As in the case with the Oxford-AstraZeneca trial, the DSMB is composed of experts who are permitted to “break the blind” at periodic intervals or when something of concern arises, meaning they are allowed to know who has received the active vaccine and who has received placebo. For statistical reasons, this cannot be done by the actual researchers, only by a group of independent experts. At the time of this writing, the DSMB was still evaluating whether the case of probable transverse myelitis was related to the vaccine. Other vaccine experts said this hopefully temporary halt in the clinical trial is not uncommon and highlights the transparency needed in developing a SARS-CoV-2 vaccine.

          There is of course no absolute guarantee that a new vaccine against SARS-CoV-2 will be 100% free of adverse side effects, including very rare serious ones. Nothing in science and medicine is ever 100%–some people who smoke cigarettes live to very old age and a rare person given an antibiotic will suffer a potentially life-threatening allergic reaction. But today there are large groups of scientists who will immediately and loudly complain if any shortcuts are taken in vaccine development, a phenomenon that has caused the administration and federal regulatory agencies to occasionally backdown on scientifically incompatible plans. There is every reason to believe that systems are in place to ensure that when the COVID-19 vaccine becomes available, it will have had as much effectiveness and safety testing as other vaccines and be safe.

          Ultimately, the risk of a new vaccine must be weighed against the risk of not vaccinating. About half of all Americans have an underlying condition that puts them at risk for severe symptoms if they get infected with SARS-CoV-2. It is possible that the FDA will grant an emergency use authorization for a new COVID-19 vaccine even before it is formally approved for everyone in order to cover those at highest risk of severe complications. We probably aren’t going to see an end to the coronavirus pandemic without a vaccine. Against all of this, the risks of a vaccine seem acceptable for most people. We are reassured right now that although scientists and people involved with clinical trials are working feverishly to develop a vaccine, despite the hurry there is no evidence yet that dangerous shortcuts are being taken that would compromise vaccine safety. If things change, however, we and no doubt many others will quickly sound the alarm.

Going Beyond the First Paragraph

How to Read a Story About Health and Science

Journalists are taught to put the most important aspects of the story they are writing into the first paragraph, called the “lede” (a deliberate misspelling of the word “lead”). Then, as they go along, more and more details and specifics are revealed. Many readers never get past that first paragraph and therefore miss all those details, a practice that can lead us astray when the article is about health and science.

         We came across a good case in point of this problem in a story published online by a group called FingerLakes1.com. As we have noted, Critica is involved in a study of how people view the safety of their municipally supplied tap water, and so we were immediately drawn to the headline “Chlorine byproduct that contaminates local tap water linked to thousands of bladder cancers in Europe.”

         The first paragraph of the story reads as follows:

The routine use of chlorine as a disinfectant in public drinking water across the Finger Lakes [a region in upstate New York] generates toxic chemical byproducts well above levels that recently triggered alarms in Europe over their links to bladder cancer.

         There is absolutely nothing false about the above statement. Chlorine is added to water as a disinfectant to kill disease-causing microorganisms, like those that cause cholera and typhoid fever. One group of chlorine breakdown products that are found in drinking water are the trihalomethanes. Last January, a European study was published in the journal Environmental Health Perspectives that claimed that exposure to levels of THMs well below the maximum allowed in the U.S. is responsible for 5% of all bladder cancers, or about 6,561 cases per year in the European Union. The report in the Fingers Lakes online news picked up on this study, as did many other media outlets.

The headline to a newspaper story may be sensational. The first paragraph may similarly reveal only the most dramatic facts. One must keep reading in order to understand nuances and complexities to any story (source: Shutterstock).

         Reading that first paragraph will understandably terrify many of us. Could it be the case that by drinking the water from the faucets in our homes we are putting ourselves at risk for bladder cancer? Should we start purifying our tap water with filters or even switch to bottled water?

Keep Reading

         Or maybe first we should read a little further down in the Fingers Lakes article. In the eighth paragraph the European publication that triggered the article is heralded as a “major” study. That’s always a bell-ringer because what constitutes a “major” study is entirely in the eyes of the beholder. The journal Environmental Health Perspectives is a peer-reviewed journal, supported by the federal National Institute of Environmental Health Sciences, so what appears there can be seen as generally good science. But this particular study is only one of many that have examined health effects of THMs (also known as TTHMs) and not all have concluded that there is a substantial risk to human health. For example, a paper published in 2019 concluded that “Causal drinking water-related bladder cancer risks remain questionable and likely small compared to other factors…” So what makes the 2020 study “major?” Perhaps only the fact that its conclusion is alarming? Is the author of the Fingers Lakes story making an unwarranted value judgment here? After all, it is highly unlikely that studies showing that THMs don’t cause health problems will attract much attention.

         The U.S. Environmental Protection Agency (EPA) places an enforceable maximum concentration level (MCL) on THMs in drinking water of 80 parts per billion (ppb). Animal studies suggest that that level is unlikely to cause the kind of cell damage associated with cancer. The Finger Lakes article spends considerable time noting instances in which the level of TCMs in drinking water in various municipalities in its area were found to be above 80 ppb. However, it is important to note that EPA mandates that water authorities monitor the levels of things like THMs on a regular basis and if they exceed the MCL they must both notify their customers immediately and take corrective action. Hence, it is unlikely that there is long-term exposure to elevated levels.

Almost all water utilities in the U.S. use chlorine to disinfect drinking water of pathological microorganisms (source: Shutterstock).

         And if you read far enough down the Finger Lakes article you come across this statement: “Despite the fact that the Finger Lakes water systems produce TTHMs at rates significantly above the European and U.S. averages, the region has not been a particular hotbed for bladder cancer, according to the state’s highly detailed cancer registry.”  A little further down you will read “…bladder cancer rates are influenced by a host of other factors besides disinfectant byproducts. Factors like smoking may be even more influential…bladder cancer rates and lung cancer have followed roughly similar trajectories, declining slightly in recent years as the prevalence of smoking has fallen off.” Now the risk of bladder cancer from drinking tap water perhaps seems a little less ominous than the headline and first paragraph would lead us to believe.

         In fact, cigarette smoking is the leading risk factor for bladder cancer, causing about 50% of all cases. Every year there are approximately 81,400 new cases of bladder cancer in the U.S., so if we accepted the European study’s finding that 5% of those can be attributed to THMs in drinking water, that means slightly more than 4,000 cases. There are also many other risk factors for bladder cancer besides cigarette smoking and the American Cancer Society does not even list THMs as among them.

A Risk-Benefit Perspective

It is also important to consider a risk/benefit perspective. What if we did stop chlorinating our drinking water? Chlorination is a relatively simple and inexpensive way of disinfecting water and killing disease-causing bacteria and viruses. Without chlorination, we would be at risk for serious waterborne illnesses like cholera and typhoid fever, both of which are extremely uncommon today in the U.S. but not so in countries that do not have modern water purification systems. The EPA mandates a detectable level of chlorine be present in drinking water, up to a maximum of 4 parts per million (ppm).

         So what are the risks and benefits of water chlorination? It is possible, although debated, that over a lifetime of drinking chlorinated water there is a small increased risk of bladder cancer. To put this in perspective, there are a little under 3 million deaths in the U.S. every year. There are slightly less than 18,000 deaths from bladder cancer annually in the U.S., so if 5% are attributed to THMs, that would be about 900 of the 3 million total deaths. And the risk of bladder cancer from drinking water is, again, unclear.

         If we wanted to avert those possible 900 deaths, we could remove chlorine from the water. It is impossible to estimate at this point how many people would get sick or die from the resulting waterborne disease that would surely follow. The World Health Organization estimates that 120,000 people die from cholera worldwide every year.

         We could institute an alternative method of disinfecting water. Ultraviolet (UV) light is an effective disinfectant. It was used in the U.S. in the early 1900’s, but abandoned due to high operating costs. Would we now be willing to install UV treatment equipment in municipalities throughout the U.S.? We were unable to find estimates about how much that would cost.

         The story about chlorine safety is clearly far more complex than is captured in the headline and first paragraph of the Finger Lakes article. If one does take the time to read through the entire article, this begins to become clear, but unfortunately, most of us do not even read a newspaper article past the headline.

         Even reading the whole article will not get you enough insight to really make an informed decision about whether water chlorination is safe. That can only come from doing further research and then doing the most difficult thing of all—making a risk/benefit analysis.

         Risk/benefit analyses are particularly hard to stomach when the risk involves deaths. We are of course highly uncomfortable with the notion that a small number of potentially preventable deaths is acceptable if a larger number of deaths can be prevented. A headline linking chlorine byproducts to “thousands of bladder cancers” obscures the fact that many more people would develop potentially fatal illnesses if we stopped chlorinating our water supply, or that the alternative to chlorination requires a decision to pay for it with tax dollars that are also needed for healthcare, education, transportation, and public safety.  Science journalists have a tough mission. On the one hand, like all journalists, they have to attract readers. They know that most people will not read much beyond the lede and therefore must cram in the most attention-getting material in a sentence or two at the very beginning. On the other hand, they are responsible for informing the public as accurately and clearly as possible about emerging science. Knowing that, it becomes critical that we media consumers always read past that first paragraph and give the journalist a chance to describe all the nuances and caveats that apply to that first paragraph. And if we don’t find them by the time we reach the end of the story, it’s time to consider doing some research on our own.

Murder is Up, Crime is Down

Does Domestic Violence Play a Role in the Paradox?

Editor’s Note: The idea for this commentary began when Antonnella Hooper of CreditCards.com wrote to us about her online guide for women in abusive relationships that “offers advice on the steps to take towards financial and physical freedom while outlining helpful resources for continued support.” She asked us to put the link to her page on the Critica website, which we do here and on our home page, and Critica COO Catherine DiDesidero suggested we do this in the context of a piece on domestic violence during the pandemic. That in turn led us to ask the question: what do scientists do when we need to answer a question during an ongoing event?”

         There is now widespread agreement based on reasonably good data that the homicide rate has increased in U.S. cities since the beginning of the pandemic. At the same time, overall crime rates have decreased. It is unusual for these to go in opposite directions and the apparent anomaly has sparked many theories. Figuring out whether any of them are true is an exercise in understanding what to make of predictions and how to use data while events are still unfolding.

         The question is, of course, whether there are sufficient data to back any of the factors proposed as causal for the observed increase in homicide rates. For example, we were especially interested in seeing whether an increase in domestic violence during the pandemic could account for the increase in homicides. But the question can be asked about any number of other putative factors, like increased gun sales, dissatisfaction with the police leading to less policing, the bad economy, and overwhelmed hospitals less able to save the lives of victims. A review in Vox last month by German Lopez is an excellent place to find the pros and cons of these and more theories weighed.

Data Snooping

         Gathering data during any ongoing event is always difficult. Even in a well-controlled randomized controlled trial (RCT), data “snooping” while the study is still being conducted is frowned upon. Besides having implications for the integrity of the study and later statistical analyses, it is always possible that what seems like a finding at one point in the study turns out to be a non-existing one later on, and vice versa.

Nevertheless, sometimes even with an RCT it is necessary to break in at some midpoint and see how things are going. In the case of an RCT, this is done whenever there is a chance that either giving or withholding a treatment might be harmful to the study participants. For many studies, ethics committees require what are known as data and safety monitoring boards (DSMB), a group of independent people who look at the data at several predetermined time points during the study and determine if any harm can be detected and if a clear finding is already apparent so that continuing the study would be unlikely to yield any further findings.

For example, suppose a new medication for a serious heart condition is being tested against an existing drug to see if the new medicine works better. Because patients are randomized to one or the other medication and neither patients nor the researchers know who is given which drug, it is possible that the new drug is causing some adverse effect that could only be detected by “breaking the blind” and having a look at the data. Similarly, it may be that the new drug is so clearly a bit worse than the existing drug that even continuing the study and adding more participants would not possibly lead to a statistically significant finding in favor of the new drug. In either case, the DSMB has the authority to order the study stopped—continuing it exposes the participants to unnecessary risk since the study is clearly “futile.”

Health Emergencies

         In a similar manner, we sometimes cannot avoid looking at data during an ongoing health emergency, even though we know that a retrospective look when the event is finally over may yield very different conclusions. Remember how we were initially told that cigarette smoking protects against serious complications of COVID-19? Other studies say exactly the opposite. Still, as in the case with the RCT described above, we may want to know if there are already danger signals, however weak, that should be acted upon before the emergency runs its course.

         If domestic violence is fueling an increase in homicides, for example, we need to know that as soon as possible in order to do whatever we can to increase prevention. That might take the form of adding personnel to social service agencies that deal with domestic violence, controlling gun sales during the pandemic (a move that would meet certain resistance), increasing the number of helplines available for women who are in potentially dangerous situations, and increasing the number of shelters for women who are threatened or already victims. That means we have to do some data snooping. In this case, however, things are certain to be much messier than would be the case with an RCT.

There are many reasons to believe that domestic violence is increasing during the pandemic, but so far data to support the prediction are sparse (source: Shutterstock).

Certainly, one can easily imagine that the pandemic would increase domestic violence for a number of reasons. During times of extreme stress, domestic violence increases. Another potential reason is that gun sales are up, a phenomenon associated with increased domestic violence.  People are trapped at home with each other, making it potentially harder for women to get away from violent male partners (the majority of domestic violence is committed by men against women). Social service agencies that ordinarily help victims of domestic violence may not be operating at full capacity during the pandemic. Early in the pandemic, the U.N. Population Fund issued an interim Technical Report in which it predicted that:

The COVID-19 pandemic is likely to undermine efforts to end gender-based violence through two pathways:

○ Reducing prevention and protection efforts, social services and care

○ Increasing the incidence of violence

Similarly, an NPR report on June 1 stated that “One consequence of COVID-19 is a projected global increase in domestic violence, including intimate partner violence.”

         But predicting something because it seems logical that it will happen is not the same thing as rigorously observing it actually happening. If we do some data snooping about domestic violence rates since March 2020, we find that so far data are “scarce” regarding any increase in domestic violence during the pandemic and mostly come from observations reported in the media. An example of the latter is an April article in the Guardian reporting that “At least 16 suspected domestic abuse killings in the UK have been identified by campaigners since the Covid-19 lockdown restrictions were imposed, far higher than the average rate for the time of year….” A paper in an academic journal noted that “Upticks in domestic violence were reported in many regions soon after stay-at-home directives were announced.”

         Strikingly, there are also findings of a decrease in reports of domestic violence. This may simply reflect increased difficulty abuse victims have in being able to call for help because they are isolated at home with their abusers. A very informal search for articles in medical and scientific journals in the search engine PubMed, which is operated by the National Library of Medicine, revealed more than a thousand articles in the last year on domestic violence in general, but we did not find any with more than anecdotal data about rates of domestic violence during the pandemic. Although there is some evidence of murder-suicides increasing specifically in which a male is perpetrator, there are indeed few data collected with any rigor.

One study that was published on August 13, after we performed our search, does suggest that the incidence of victims of domestic violence reporting to a single Boston hospital’s emergency department (ED) was higher during the pandemic period so far compared to similar periods in the last few months. Moreover, the severity of the physical injuries was worse since March 2020. Although an important paper, it does represent only one hospital’s experience and therefore does not by itself make the case.

         The data aren’t any more solid for the many other reasons given for the increase in homicides. It is important to note that even with this increase, the rate of homicides in U.S. cities is still below what it was ten years ago. American cities are significantly safer now than they used to be. We can see, however, that getting a grip on even one of the potential reasons is complicated.

There are different ways to get data on domestic violence—reports from helplines, social service agencies, and emergency departments are among them, but each of these requires that someone makes the report. That means that there is inevitably going to be a lot of missing data. Even if scientists design a survey with good scientific properties, it is hard to know what the comparable “before” rate should be. The standard statistic usually given is that one in four women and one in nine men are victims of domestic violence. As mentioned above, however, domestic violence is believed to be significantly underreported, so unless the researchers happened to have used the same methods in the year before the pandemic, it may be difficult to know if the rate during the pandemic has really changed, especially if underreporting is even more widespread now.

Perhaps a better way would be to count the number of deaths from domestic violence using publicly available FBI crime statistics. This too may entail some technical difficulties.  In 2019, a rise in deaths from domestic violence was reported, from 1875 in 2014 to 2237 in 2017. If the rate continued to increase in the year before the pandemic, we would then need to demonstrate a significant increase in the rate of rise during the pandemic to show that domestic violence is a contributor to the overall increase in homicides.

Of course, the increase in homicides observed during the pandemic is likely to be caused by multiple factors. That will make it only that much more difficulty to see a clear signal from any single factor, like domestic violence. And—hopefully–this increase in homicides itself could be a transient phenomenon. If so, depending on what time frame is used, researches may observe very different phenomena.

These considerations show some of the difficulties researchers have in looking at data in the middle of any event, be it a well-controlled study or an international disaster. In the case of understanding whether domestic violence (or any other factor) is responsible, we have myriad technical difficulties including underreporting, lack of a clear baseline, and multiple contributing factors. The result of all of this is that at present we cannot be sure whether or not domestic violence or any other of the proposed factors is a contributor to the surge in homicide rates since the pandemic began.

It is thus always problematic to listen to predictions of what might happen when biological systems, like human beings, are involved. Yes, it seems fully logical that the pandemic would increase rates of domestic violence and therefore of deaths due to domestic violence, but in science what is seemingly logical often turns to be either only part of a picture or even completely wrong.

Public Policy Implications

What can interim data therefore add to the conversation about homicide rates and domestic violence? We have one solid piece of data—that homicide rates went up following the beginning of the pandemic. We have two hypotheses: that domestic violence rates have also gone up and that these are at least partially responsible for the increase in homicide rates. We have an incomplete dataset to address these hypotheses, although we must be clear that this also means we cannot rule either hypothesis out. Moreover, we do have anecdotal data that domestic violence has increased.

Domestic violence is obviously a terrible thing, so would there be any harm in accepting the theory and anecdotal data that it is getting worse and taking action? We can think of two possible issues. First, increasing staff at hotlines and social services agencies and creating more shelters would obviously cost money at a time when governments and nonprofits are strained for funds. Second, focusing on one potential factor could mean that less attention is spent on addressing others, such as reducing gun sales and improving policing.

Despite these potential concerns, we think policymakers should assume for now that domestic violence is a worsening problem and, while balancing other priorities, reinforce education, outreach, and service efforts to help its victims. While we should of course call for more research and better data, we find the threat of increased domestic violence and intimate partner murder to be sufficiently compelling from this bit of data snooping to warrant appropriate action.

We may be wrong, of course. But resources for women suffering from abuse have always been under funded and for some completely unavailable. Hence an increase in funding now would never be wasteful given the enormity of the problem.

When anyone predicts that something will surely occur, as they have about domestic violence, we always need to ask if that prediction is based on more than just logic, because the data sometimes defy logic and common sense. As long as we know we have entered an area of uncertainty, it still may be necessary for us to use the scraps of information we have in order to save lives.

The Psychology of Wearing a Mask

Mask-wearing is more complex than politics alone.

Much has been said about the political divide over the willingness to wear a face mask in order to reduce the spread of the virus that causes COVID-19 (SARS-CoV-2). According to some surveys, more conservative people are less likely to wear them, often on the grounds that it violates their civil rights. That research seems solid to us, but we are not political experts and wondered if there are psychological reasons that influence some people to refrain from face mask-wearing.

Psychological Factors with Some Empirical Support

A psychological reason was revealed by a recent New York Times map of who is wearing masks in the U.S. By obtaining 250,000 responses, the study is able to give a more detailed geographical picture than just at the state level. What the Times found is that there are clear clusters of people who do and do not wear face masks. The basis for this, according to Elizabeth Dorrance Hall, a professor at Michigan State University, who is quoted in the Times article about its study, is “peer pressure.”

An effect closely related to social pressure is culture. Although as we mentioned earlier, most Americans now say they accept that wearing face masks is important, that majority hovers around 80 percent, significantly less than the universal adoption of face masks for which public health officials and scientists are looking. Many have noted that people in some Asian countries have a long tradition of wearing face masks to control the spread of infectious disease and some of these countries, like Taiwan and Vietnam, had much lower rates of COVID-19 than were seen in the U.S. and some European countries. Thus, a culture of face mask-wearing may provide an enduring psychological motivation.

Dragana Gordic/Shutterstock
Source: Dragana Gordic/Shutterstock

Another psychological factor is likely to be how one judges risk. Face mask use is highest among people who know others who have been infected and/or live in communities with higher rates of COVID-19. This is an example of the availability bias—we act on things that are most easily called to mind. Reading about COVID-19 in another part of the country or about CDC guidelines for wearing face masks in the newspaper or social media may seem removed from a person’s own experiences and therefore they will minimize the risk to themselves and their families. On the other hand, there is a more immediate effect when one knows specific individuals who have been infected or hear about people living nearby who have succumbed to SARS-CoV-2. That raises the risk assessment the individual makes, which in turn motivates a change in behavior toward wearing a mask.

Another important psychological factor may be the feeling of confusion that was exacerbated by early CDC and WHO advice. As the pandemic unfolded in February, the CDC first insisted that face masks were unnecessary for healthy people. Then in early April, CDC issued new recommendations that called for wearing face masks in certain crowded public situations. It was not until June that CDC issued guidelines calling for everyone to wear cloth face masks in publicWHO was also criticized for not recommending that everyone wear face masks until June. Confusion about something is often dealt with by ignoring it; that is, if people cannot be sure what is the right thing to do with respect to face masks, they may default to a position of just not thinking about the issue and therefore not wearing them.article continues after advertisement

Yet another psychological factor to consider is a sense of control. One thing we can certainly say about COVID-19 is that it makes us feel we are out of control. Although experts rightly tell us there are things we can do to control the pandemic (i.e. social distancing, wearing face masks, frequent handwashing, and getting tested), there is little we can do personally to affect businesses closed all around us, children not able to go to school, and people dying. Refusing to wear a mask may seem, paradoxically, like taking control of the situation. No, it is not a rational step because doing so will only make things worse. But to some, refusing the mask may seem like a major personal statement that re-establishes a sense of control.

Overcoming the Psychological Factors

While it is beyond our expertise to recommend how to convince people who refuse to wear face masks for purely ideological reasons (e.g. “It is a violation of my First Amendment rights”), there may be some things we can do to overcome the more psychological factors that determine face mask-wearing.

Let’s start with a thought experiment. Ask a person who is uncertain about wearing a mask whether they would want surgeons who aren’t wearing surgical masks to operate on them or a member of their family. Most people will likely think that idea is dangerous and even absurd. In fact, there is something we regard as almost heroic in the image of the surgeon in her surgical gown and mask. Then remind the person that the reason why surgeons wear masks, even though they themselves feel perfectly healthy, is that it cuts down on the risk of passing off an infection to the patient undergoing surgery. This creates a positive role model for wearing face masks to prevent the spread of COVID-19.

To combat social pressure against wearing a mask, we need to make sure that everyone everywhere sees people they trust and respect wearing masks. Let’s go to communities where mask-wearing rates are low and find out what public officials, celebrities, actors, and sports figures the people there respect. Then let’s ensure that people in these communities see plenty of their heroes, be they surgeons or basketball players, wearing masks. Finally, we need everyone in responsible public health positions to stop equivocating about face masks and to make definitive and clear statements. We may have trouble changing fixed political convictions about face masks, but perhaps we have a chance to change the psychological barriers to wearing them.

How to Purify Water: 13 Methods for Homes and Outdoors

Editor’s Note: Critica follower James Clayton, owner of Ro-System Reviews, is interested as we are in drinking water safety and shared this interesting piece on water purification with us. 

Knowing how to purify water at home and in the outdoors is an essential survival skill. The human body can live for over a month without food, but can only last three to four days without water.

One of the first and primary skills survival experts focus on is how to get access to safe, clean, and drinkable water. Water is so essential that it is important to know how to make water safe and drinkable.

If you live in the United States and you get your water from the city, it is mostly safe to Drink. If you have a personal well, it would depend on the location and how deep the well is. Tap water is regulated by the federal Environmental Protection Agency (EPA) and by state and local authorities. Well water, by contrast, is not regulated by EPA, may or may not be regulated by state and local authorities and may contain contaminants at levels that exceed EPA standards. Perhaps the most serious water problem regarding water safety in the U.S. is the nearly 2 million Americans who do not have access to potable water at all. When in doubt, you should contact your local authorities for location-specific information.

How to purify water: 13 methods

The following lists many ways to purify water. Each method has its own advantages and disadvantages, and depending on the need, how much prep time you have, and access to materials will determine which method is best for you.

However, no matter what method you use, you will also want to know how other water purification systems work.

1. Boiling

Boiling water is just what it sounds like. You take a pot, fill it with water, add heat until the water boils, and once the water cools it should be safe for drinking. This is a common method for sources of water that may be contaminated with pathogens, bacteria, and other unsafe organisms.

How it works

Boiling water kills unsafe pathogens, bacteria, and other unsafe microscopic organisms that may be living in the water. In areas where the water is known to be infected with these harmful microscopic organisms, it is important at the very least to boil your water.

What does it remove?

Boiling the water kills harmful microscopic organisms that can make people sick if consumed.

How to do it

Boiling water is extremely easy. Some people boil their water just to be safe, even if there are no known pathogens or bacteria issues with the water. You will need a pot to hold the water, and a heat source like a stove. Simply fill the pot with water, and then heat the pot until the water is at a rolling boil. Once the water has cooled again, it is now safe to drink.

Advantages and disadvantages

Some of the advantages is that this is super easy to do. Anybody can boil their water if there is a concern that it may be contaminated with harmful microscopic organisms. It requires no special equipment, and everyone should have some way to boil water.

Some of the disadvantages is that people who drink boiled water often complain that the water has a metallic taste. Also, this method only deals with eliminating pathogens, bacteria, and other harmful forms of microscopic organisms.

It will not remove any other pollutants that may be in the water such as mud, chemicals, or other harmful materials. It only kills the potentially harmful microscopic organisms.

2. Iodine

Iodine is another method that has been around for a long time to purify water. Using iodine may not have been around as long as boiling water, but it is still a proven method for purifying water quickly and reliably.

How it works

Iodine either comes in tablets that will dissolve in water or in drops. Iodine is the favored method for purifying water in outdoor wilderness survival type settings.

It works similar to boiling water by being very effective at killing harmful pathogens, bacteria, and other microscopic organisms in the water.

What does it remove

Iodine has been proven to be quite effective at killing pathogens, bacteria, and other microscopic organisms from the water. It does not remove other pollutants, chemicals, and other harmful substances in the water.

How to do it

To purify water using iodine, simply dissolve an iodine tablet into water, or put a few drops into the water depending on how your iodine is packaged. There are instructions on how much water should be used per drop or tablet, and should be on the container that your iodine comes in.

Advantages and disadvantages

Using iodine is quicker and easier than boiling water. So in a wilderness situation there is no need to create a fire or use a propane stove, all you need to do is combine the water and the iodine, and the water should now be safe to drink from pathogens, bacteria, and other harmful microscopic organisms.

This is the preferred method of backcountry hikers, who have access to natural sources of water that are free from pollutants, but may still have some harmful microscopic organism living in the water. Iodine is small and easy to carry, and very quickly the water is safe to drink.

Iodine will not remove any other pollutants from the water. So it is important to have a source of water that is pollutant free, and just needs to be treated for harmful microscopic organisms.

Also iodine can be toxic if taken in large amounts, and some people have an iodine allergy. If someone has an iodine allergy, is pregnant, or has a thyroid issue, then iodine should not be used to purify their water.

Also, it can discolor and change the taste of the water. Many find this unpleasant enough, to discourage use of iodine to purify their water

3. Chlorine

Chlorine plays a major role in most modern water purification systems for cities and other municipal water sources. It has become essential to treat most municipal water systems, and may be used in a survival situation carefully when a source of water may have become compromised.

How it works

Chlorine is an efficient choice to kill harmful microorganisms that could be living in the water. It if effective enough for large scale use and may even be used in survival situations.

Chlorine works by killing the harmful pathogens, bacteria, and other microscopic organisms that can be living in the water.

What does it remove

While it kills deadly microscopic organisms that may be contaminating the water, it does not remove any particles or other pollutants.

So using chlorine to purify the water may need to be treated also to remove any other pollutants that would still render the water unsafe to drink.

How to do it

If the water cannot be boiled, and there is no access to iodine, then regular household bleach can be used to make water safe to drink from harmful microscopic organisms.

However this must be done with great care because too much can be harmful. Using unscented laundry detergent, or unscented bleach is the yields the best results. It takes about 8 drops of bleach per five gallons of water.

Advantages and disadvantages

The advantages of this method are that it will definitely kill all of the pathogens, bacteria, and other microscopic life that could be harmful if consumed.

If mixed properly and in the right amounts it also does not significantly alter the taste of the water. Most cities use chlorine in their municipal water systems, because it does not change the look of the water, and does not alter the taste of the water. Because of this, cities use chlorine with some type of filtration system to take care of their cities water.

The biggest disadvantage to using chlorine long term to purify your source of water is that there may be some long-term health effects of consuming too much chlorine. Several metabolites of chlorine have known carcinogenic properties in animals. This is not considered a significant problem when the amount of chlorine in drinking water falls within EPA standards, but could be problematic if chlorine levels exceed those standards. Also, chlorine does nothing to filter out other pollutants in the water.

4. RO machines

Reverse Osmosis (RO) machines used a water pump, and a semi permeable membrane to rid the water of pollutants.

How it works

Reverse osmosis machines are whole-house, under-counter, or countertop appliances. It is not a passive system, but uses a pump to build up water pressure to force the water across a semi permeable membrane.

This removes many of the microscopic organisms that are in the water as well as many pollutants that are in the water.

What does it remove

It removes from the water most of the pathogens, bacteria, and other harmful organisms in the water. While it does not kill these microscopic organisms, it may remove some of a certain size (depending on the type of filter). It also removes many of the pollutants that are in the water as well, such as sediments, salt, pollutants, herbicides, and pesticides.

How to do it

Using a water pump the machine pumps the water across a semipermeable membrane. As the water is forced across this membrane it leaves behind various pollutants. Some of these machines can take out some microscopic organisms if they are large enough, however most machines do not.

Advantages and disadvantages

If you are getting your water from some type of city municipal water system, then it should already be treated for harmful microscopic organisms. This system will then take out other unwanted contaminants such as sediments.

While this works great if you live in a city or there is another water purification system that is already at work, this is not enough to be the sole means of purifying water.

It needs to be used in conjunction with another system that will clean out the harmful microscopic organisms. Also it needs a reliable source of electricity to work, which may not readily be available in a survival situation.

5. Gravity filters

A gravity filter uses gravity to pull water through a filter which is used to purify the water. The process can be time consuming, and the materials may be somewhat expensive.

Also, this is possible as a DIY project, and many people in long term survival like situations will use some type of gravity filter for their long term water needs.

How it works

A gravity filter simply uses gravity to pull water through a filter. This is a passive yet time consuming activity when done correctly should yield perfectly good drinking water.

The concept of a gravity filter is similar to how the earth purifies water over time. In nature as water sinks through layers of soil, rocks, and other substrate, the water is slowly cleaned.

When the water eventually emerges in a natural artesian spring it is pure, and generally safe to drink without being treated further.

What does it remove

A gravity filter will remove pollutants and all types of particulate matter. If constructed properly it should also be able to remove many bacteria and some microscopic organisms.

How to do it

You can buy portable gravity filtration systems, that require no power. This is ideal in any survival situation, or for living off the grid. If you are in a situation where you need to create your own gravity filter, then you can create your own relatively easily. You would need at least two containers, one on top of each other.

The bottom container catches the water once it has gone through your gravity filter. The top container should feed into the bottom container, and this should have all of your layers that your water should pass through.

It should have a mix of layers such as charcoal and stones, this will be the filters that the water will slowly pass through.

This takes a little bit of trial and error at first to get right, but you can also consult the internet where many people have, put up detailed plans for free. Also, many reputable vendors sell high quality gravity filters.

Advantages and disadvantages

One of the greatest advantages of the gravity filter is that it can be built with relatively inexpensive materials, and is the most natural way to purify water. Also, there are some great tabletop gravity filters that are available for sale online.

The gravity filter requires no power, and as long as you have time, then it is an extremely efficient water purification system.

The biggest disadvantage is that it will remove most but not all potentially harmful organisms. Also, the homemade versions tend to be fairly large and are not easily portable.

The ones that are available for sale has changeable filters that tend to be expensive, and the filters need to be replaced regularly to remain effective.


6. Make a DIY filter

It is fun and easy to make your own water filter at home. You can use items that you most likely have lying around the house to make a water filter that will get a lot of dirt and other pollutants out of your drinking water.

How it works

This DIY filter is going to use gravity and some materials you most likely have already to make a filter. First you are going to gather a soda bottle, a coffee filter, some cotton balls, activated carbon (or charcoal), sand, and some small pebbles. Now even if you do not have these items at home they are readily available.

The activated carbon may be the hardest to find. However, you can either make your own with some charcoal (and other ingredients), or buy some at any local pet store.

What does it remove

This DIY filter should remove all the big stuff out of the water. It should clean out all of the dirt, sediment, and other large pollutants from the water.

It will not address harmful microscopic organisms or harmful chemicals that may be in the water. So if this is used to drink pond water for instance, then this should still be boiled first to kill all of the harmful microorganisms.

How to do it

Cut off the bottom of the soda bottle and turn it upside down. Open the soda bottle and but the coffee filter over the nozzle of the bottle to keep everything in the bottle and to have a bit of extra filtration.

Then create a layer with the cotton balls, a layer of activated carbon, a layer of sand, and a layer of small pebbles. Once all your layers are in place, the filter is ready to be used.

Since the bottle is upside down it should be hung and allowed to drain into a bucket or bowl.

Advantages and disadvantages

The greatest advantage to this method is that anyone can do this. It is a cheaper and easy filter than anyone can make with a little bit of work, and a quick trip to the store. This is a great DIY project if a situation arises that calls for being able to purify water at home.

The biggest disadvantage to this is that is a painfully slow method of filtration, and the water will still need to be boiled or treated to deal with potential microorganisms that could be harmful. However this is an effective water filter, and it is a great DIY project to learn more about how water filtration works.

7. Pitcher filters

A pitcher filter uses some type of ceramic or carbon filtration system that is inside of a water pitcher. This is probably the most common type of water filter. They are a convenient and relatively quick way to enjoy good quality filtered water.

How it works

A pitcher filter works by using a filter element that is embedded into the top of the filter. Water is poured into the top of the pitcher where it is then passed through a filter to the bottom of the pitcher.

After the water is gone from the filter section, then the pitcher is ready to use. The filter element is typically made of activated carbon and works through absorption, and the filter must be replaced every few months or so.

What does it remove

This will remove large sediments and pollutants. It will normally not remove any type of microscopic organisms. However if there is a heavy water issue such as lead, copper, or mercury in the water then this is a great solution to remove large pollutants from the water.

How to do it

A pitcher filter needs to be bought from a store or other online vendor. It is similar to a gravity filter as it uses gravity to pull the water though its filter, but it will not filter as many things out of the water as a good gravity filter.

Advantages and disadvantages

In terms of convenience the pitcher filter is one of the best options. The pitcher filter if very popular, especially for people in cities who have access to municipal water that have been treated for microbes, but want to remove things that municipal water systems do not deal with such as certain metals or other materials that could be in the water.

8. UV light

UV Light purifies water that may be unsafe because of microscopic organisms using ultraviolet light. This is a water filtration system that does not deal with pollutants but deals exclusively with microorganisms.

How it works

It uses ultraviolet light that is harmful to microorganisms that may be in the water. It scrambles the microorganism’s DNA so that they are no longer able to reproduce.

The biggest danger in drinking water contaminated with microorganisms is that when many of them find their way into a person’s digestive tract they settle down and begin to reproduce.

This can lead to a person drinking the water infested with these microbes to become sick or even seriously ill. The ultraviolet light renders the organisms unable to reproduce, and they will simply pass through your system.

What does it remove

It does not truly remove anything. Instead it sterilizes the microorganisms that could be in the water, so that they cannot reproduce inside of a person and make them sick.

How to do it

This is not a do it yourself type of project. This is something that is going to need to be bought from a retailer that specializes in producing ultraviolet light to treat the water for microorganisms.

Advantages and disadvantages

While if you already have access to water that is free from pollutants, and only need to deal with a microorganism contamination issue, then this is a great solution. It does not take a lot of power, and it leaves in some health microbes that are actually healthy for the human body to consume.

The main disadvantage is that it is not actually taking anything out of the water or adding anything that could be helpful. This needs to be paired with some other type of water filtration system that will take out all of the other pollutants in the water.

9. DIY solar distillation (evaporation trap)

Knowing how to use solar distillation to create your own evaporation trap can be crucial in a life or death survival situation. The evaporation trap, uses a process that takes place naturally on earth, that naturally filters water of both pollutants and microbes. It can be made with a variety of materials that could easily be available in a survival situation.

How it works

It works by using evaporation to naturally separate water form contaminants, pollutants, and microbes. It uses the sun to heat the water and cause it to boil off as steam. Then a collector is used to collect the pure clean water, while the contaminants tend to rest on the sides of the evaporation trap.

What does it remove

An evaporation trap will remove both microbes and pollutants if used correctly. A evaporation trap does not make a lot of water, but in a survival situation even a little bit of water can make the difference between life and death.

How to do it

While you can buy a solar distillation (evaporation trap) commercially as a survival kit that you can take with you for emergency situations, an evaporation trap is something that you can easily make on your own from materials readily on hand.

This can be made by digging a hole and using a tarp, or using some water bottles duct taped together. There are a lot of great DIY evaporation trap projects online.

Advantages and disadvantages

The main advantage is that with a little bit of knowledge, and some very common materials there should always be access to reliable water no matter what conditions are going on.

While this is not the easiest way to get purified water, with a bit of practice this can be a reliable source of water in even the harshest conditions.

10. Survival straws

A survival stray is a device that can be used to drink water from almost any source. It is often used by those who engage in outdoor wilderness activities who may be far from more reliable sources of water. It is a great tool to be a part of any survival kit, and can mean the difference between life and death in survival situations.

How it works

The survival straw works through suction. When a person sucks on the straw it draws the water up through a microfiber filtration device that removes contaminants. This is a powerful tool that uses a natural suction power to filter a source of water, and makes it safe for its user to drink.

What does it remove

The survival straw removes bacteria, parasites, and microplastics. It does not remove salt and other dissolvable substances that may be in the water.

How to do it

The survival straw is not a DIY project and should be purchased from a reputable vendor. These durable and lightweight survival tools last a long time, and most are good for slurping up over 1,000 gallons of water before needing to be replaced.

Advantages and disadvantages

The main advantage of this product is that it is extremely portable, and can easily be packed to be used in any type of survival situation. It may not be able to purify salty water, but in a pinch it can be used to safely drink many natural put unsafe sources of water that may be encountered.

11. Ozonation

Ozonation is a process by which ozone is added to water by an ozonation machine. Ozone, also known as molecular oxygen, is the most stable form of oxygen, with oxygen being chemically bonded to itself. Ozone has a lot of purported health benefits.

How it works

Ozone is added to water by treating the water in a machine that is designed to add ozone to the water through a process of electrical discharge.

This process would happen naturally in the environment by a high electrical discharge such as a lightning strike. However, an ozonation machine can be used to create this type of water.

What does it remove

This process can be used to add a negative charge to the water, which may have some health benefits, and it is also very useful at dealing with harmful microorganisms without adding harmful chemicals.

How to do it

You can purchase an ozonation machine for home use. This is a system that needs to be plugged in to be used, and so in a survival situation it will not be of much use. However, many people have a countertop machine at home, and enjoy this water very much.

Advantages and disadvantages

The biggest advantage to this method is treating the water for dangerous microorganisms without having to use harmful chemicals, boiling the water, or other methods to deal with the potential dangerous microorganisms.

Also, many enjoy the taste of this type of treated water, and there may be some great health benefits as well.

The biggest drawback to this method of course is that it is a fairly large appliance that needs to be plugged in to do its job. This can be a real setback in a survival situation, but it should be fine for regular home use.

12. Purifying with plants

It is a little-known fact that certain plants can be used to make water safe to drink from potentially harmful microorganisms.

How it works

Purifying water with plants works by soaking the plants in the water. This releases naturally occurring antimicrobial substances into the water, that kill the harmful microorganisms. This will make your water safe to drink form harmful microorganisms.

What does it remove

This method will deal with harmful pathogens, bacteria, and other microscopic organisms. However it will not deal with dirt, sediments, or other pollutants in the water.

How to do it

There are a variety of plants that will purify water when soaked and these include:

·   Banana Peels

·   Fruit Peels

·   Jackfruit Seeds

·   Reeds

·   Bulrushes

·   Rice

·   Coconuts

·   Java Plum Seed

·   Moringa Oleifera

·   Oregon Grape

·   Other Citrus Fruits

Advantages and disadvantages

The biggest advantage to this method is that it naturally deals with harmful microorganisms in the water, and often adds a nice flavor to the water.

This takes extensive knowledge of local plants, or access to these from a local grocery store. However, it is a great way to add flavor and improve the quality of your water, especially for at home use.

The biggest disadvantage to this technique is that in a survival situation a vast knowledge of identifying wild plants is needed. Identifying plants in the wild is not easy.

Also, many of these plants are specific to certain geographic locations, so unless you are in the right place, at the right time, then this may not help much.

13. Sedimentation

Sedimentation is a physical water treatment process that uses gravity to remove pollutants such as rocks, dirt, and other large solids form water.

How it works

This process takes place in sedimentation tanks or basins. As dirty water if brought into the basins it is moved through the tank with a steady current. As the water passes through the sedimentation tank large solids settle to the bottom of the tank.

As the water moves out to the sedimentation tank it leaves these large pollutants at the bottom of the tank, and the cleaned water is now ready for further treatment and filtration. This is usually one of the first steps in a large municipal water treatment procedure.

What does it remove

It removes large pollutants such as dirt, rocks, and other large solids from the water. However the water is still not fit to drink, and must be further processed for both harmful microorganisms, and further filtered for other solids that may still be in the water.

How to do it

This process takes advantage of a physical property where sediments in water tend to sink to the bottom of a tank. This allows the a layer of sediment (or muck) at the bottom of the tank to be separated from the partially cleaned water near the top of the tank.

This is accomplished through a mechanical device actually scraping away the muck at the bottom of the tank, and the cleaner water flowing out of the tank. After the water passes through several of these types of tanks it should be ready for further processing.

Advantages and disadvantages

The biggest advantage of this method is that it takes advantage of the physical properties of sediments in waters tendency to sink to the bottom.

Once this system is set up, it can go a long time without further maintenance, and makes it easier for further filtration and dealing with any harmful microbes that may be in the water.

The biggest drawback to this method is that it takes large tanks to make this practical, and the water is still not considered safe to drink after going through sedimentation and will still need further processing.


Learning how to make water safe is an important survival skill. Whether you are at home or outdoors it is vital to understand how to purify any source of water.

Sea Sick: The Global Ocean in Crisis, by Alanna Mitchell

Book Review 
Contributed to Critica by Peter McKenzie-Brown

I bought this book when it first came out but didn’t read it until I found myself in the Coronavirus lockdown, some ten years later. The book is terrific, and I have found out that author Alanna Mitchell later turned it into a one-person play, which she performed across Canada and around the world until, one presumes, the pandemic began.

A Canadian journalist, author, and playwright, Alanna Mitchell says on her website that she is “fascinated with the intersection of science, art and society.”   

She titled this book Sea Sick – not “Seasick,” please note. She writes intelligently and passionately, and travelled around the world to do her research. The book is strongly based on science. “The issue is that all over the world,” she writes, “groups of specialists who rarely put their information together, are finding that global climate change and other human actions are beginning to have a measurable effect on the ocean. The vital signs of this critical medium of life are showing clear signs of distress.”

Mitchell writes about a much greater problem than the well-known idea that oceanic fish and other species are in decline. The ocean, she explains in the prologue, contains some 97 percent of Earth’s water, covers more than 70 percent of the planet’s surface, and makes up 99 per cent of our world’s living space. “Even more significant than the ocean’s breadth and width is its depth, or third dimension” she continues. “That total volume, with its immense biological importance, is what I came to think of as the deeps – both the source of life and the future of life on the planet.”

To research this book, she visited the ocean’s threatened areas, where she saw the tragic results of human ignorance and irresponsibility, and talked to scientists who may be able to suggest solutions. Her writing is riveting; her travels, delights; and her findings, intellectually stimulating. Here are a few examples.

Australia’s Great Barrier Reef she calls “The Last Best Place on Earth.”  But the corals that made the reef are dying, she says. “The worldwide decay of coral reefs – caused by the pollution from land, too much fishing, nasty practices to capture wild fish for the aquarium trade and waters that are too hot because of global climate change – has already started to take its toll.”

Another example, closer to home. In the Gulf of Mexico, there are enormous “dead zones” – oxygen-free regions where nothing can live because of the toxic chemical runoff into the delta of the Mississippi River system.

In Plymouth, England, she visited a marine laboratory where a precipitous decline in plankton is being studied, a problem she calls “maybe the most important question human beings will ever grapple with.” Plankton forms the bottom layer of the entire oceanic food pyramid, so anything that happens to plankton affects everything that lives in the ocean. Also, it affects land animals whose diet includes seafood – for example, people on every continent  including, one assumes, research scientists active in Antarctica.

Her book is not only backed up by travels, but by interviews with researchers, and by reference to their work. For example, she cites a 2006 paper titled “Impacts of Biodiversity Loss on Ocean Ecosystem Services” led by two profs at Canada’s Dalhousie University – Boris Worm and Ransom Myers – that is dreadful in its conclusions. According to these researchers, in the half-century since industrial fishing took hold in the world’s oceans, 90 per cent of all oceanic predatory fishes – cod, tuna, swordfish, sharks – were gone. Today, we are fishing the few remaining percentages. Fish farms are today’s answer to the virtual absence of wild fish in the ocean – an absence brought on by overfishing. More than half of the seafood we and our pets consume today – a decade after Mitchell published her book – is the product of aquaculture. Raising saltwater fish takes place in farms in the ocean itself, with species confined  in mesh cages too deep for them to escape, with much of their food being sea creatures that can float or drift on currents through the mesh.

She also went to China, the world’s largest emitter of greenhouse gases, where the waters are polluted – often by the vast pens the Chinese use to raise more farmed fish than any other country. China now provides 62 per cent of the world’s farmed fish.

Mitchell’s final trip is to the Florida Keys, the last research expedition of the book, where she had the opportunity to go to the ocean’s bottom in the submersible vessel Johnson Sea Link. When offered the ride, her immediate reaction was, “Why keep going? Why should another research trip make any difference?”

It did, though. As the submersible sits on the bottom, she had a kind of epiphany. “Shivering in my undersea womb, peering at these wondrous, ancient life forms,” she writes, “it occurs to me that we are in an era that holds out the potential of magnificent regeneration. We could, if we wanted to, form a new relationship with our planet. We could become the gentle symbionts we were meant to be instead of the planetary parasites we have unwittingly become.”

In conclusion, I cannot recommend this book too strongly; it dazzles. Mitchell explains the oceanic problems grippingly. Many of her chapters chronicle adventures in which she accompanies scientists at various research missions around the world. At least as importantly, her writing is engaging and balanced. This book rocks.

Combating Misinformation about Water Safety on the Internet and in Social Media

Editor’s Note: This article was published in the Penn Water Center’s Publication “Water Exchange” on July 16, 2020.

Alumni Views

By Jack M. Gorman MD, David A. Scales MD PhD, Cody M. Leff, and Sara E. Gorman PhD MPH

July 16, 2020

Misinformation about science and health is rampant on the internet and throughout social media, as attested to by the current WHO-declared coronavirus “infodemic.” Because so many people now seek information and advice about personal health decisions on the internet, such misinformation has the potential to cause significant harm. Parents believing that vaccines cause autism and refusing to immunize their children, or people with cancer shunning traditional treatments like chemotherapy are examples of harm being caused by misinformation promulgated on the internet and social media.

We are Penn undergraduate alumni who formed a non-profit organization called Critica with the goal of improving the public’s acceptance of scientific consensus, counteracting misinformation about science and health, and increasing the use of scientific evidence in public policymaking. Initially, we focused our attention on vaccines, GMOs, nuclear energy, climate change, Lyme disease, and personal gun ownership. More recently, after conversations with the Robert Wood Johnson Foundation, we added the safety of municipal drinking water in the U.S. as an important topic for which the public should be provided scientifically accurate information and given guidance against misleading or incomplete information. Because this was not an area where any of us had significant background, we sought collaboration with The Water Center at Penn.

We quickly learned from our Penn Water Center colleagues that the American public tap water supply is safer than it has ever been and is the safest in the world. We also identified multiple areas in which misleading claims about contamination and toxicity of our drinking water are spread through the internet and social media.

Perhaps the most obvious topic where information regarding tap water is misrepresented is the persistent rumor that fluoridation of water causes a myriad of health problems. There is little scientific debate that fluoride at appropriate concentrations prevents tooth decay in children and adults. In fact, the U.S. Center for Disease Control and Prevention (CDC) declared community water fluoridation one of the ten greatest public health achievements of the 20th century. 

Despite endorsements by many scientific and medical organizations, including the American Dental Association and the American Academy of Pediatrics, claims persist that fluoride in drinking water causes medical harm. It is true that at very high levels, fluoride can cause toxicities resulting in abnormalities to skeletal bone, teeth, and the thyroid gland. However, to protect against this, the Environmental Protection Agency (EPA) sets a maximum level of fluoride allowed in drinking water of 4.0 parts per million (ppm) and recommends that fluoride levels be maintained at a minimum of 0.7 ppm to protect dental health. Studies show that in this range, fluoride’s benefits in decreasing tooth decay outweigh any risks of harm. A study in Juneau, Alaska, serves as an example. In 2007 the city voted to stop fluoridating its public water supply, which resulted in a 25.2% increase in tooth decay in children and adolescents.

Most recently, concerns have emerged that children exposed to fluoride in tap water either during prenatal life or infancy can show adverse neurodevelopmental outcomes, particularly lower IQ.  These concerns stem from a 2019 draft report from the National Toxicology Program, which concluded that fluoride is “presumed to be a cognitive neurodevelopmental hazard to humans.”  While this assertion has been challenged by many experts as well as a report from the National Academies of Science, Engineering, and Medicine, information from the 2019 draft report promoted through social media and internet channels has nonetheless promoted increased debate about the safety of fluoridation of the public water supply.

This situation highlights two common challenges faced by those of us interested in counteracting misinformation about science and health. First, it is understandable that people believe information presented by scientists or scientific organizations without considering the aggregate scientific data, especially when there is some disagreement within the scientific community itself. Hearing that a report from a national scientific agency links fluoride to neurodevelopmental problems is going to make some parents anxious about fluoride’s safety. We need to correct misinformation while at the same time respecting understandable fears and anxieties.

Second, it is frequently difficult to convey risks and benefits to people who do not possess a scientific background. At the levels of fluoride allowed in drinking water, most scientists and health professionals conclude that the benefits far outweigh the risks and that fluoridation is worthwhile to protect the public’s health. But such risk/benefit assessment may not persuade the general public. Studies show that people tend to overestimate very small risks and that some people cannot tolerate any risk. We cannot tell people there is absolutely zero risk that fluoridation will cause harm. We can only say that the benefits of reducing tooth decay and oral infections are far greater than any risk associated with fluoridated drinking water. In explaining this, we need to walk the fine line of acknowledging risk and encouraging rational assessment of that risk. 

To counteract misinformation about health and science, we needed to explore the most effective and respectful ways of promoting accurate information about issues like the risks and benefits of drinking water fluoridation. We searched the literature for studies of various methods that have been shown effective in dissuading people from believing misinformation. Most of these studies have been conducted in the laboratory and the majority involve political and public policy statements. Nevertheless, we were able to draft a protocol for counteracting online misinformation in the health and science fields.  

Our approach is to enter into a thread of comments on an internet or social media site that begins with some misinformation about drinking water safety. Our CIO, Cody Leff, has developed a method that permits us to pick out stories in traditional media and review them for accuracy. We then use Crowd Tangle software to locate social media sites in which an inaccurate or misleading statement based on the original story is repeated and discussed. 

Our protocol is based on a psychological intervention called Motivational Interviewing (MI) that was originally developed to help people with substance use and mental health disorders find reasons to pursue treatment. Of particular importance to us is the MI method of establishing common ground with an interlocuter, which is essential for initiating the counteracting protocol. We proceed through the protocol steps including asking the person who has posted the misinformation to explain the scientific basis for their statement; warning or “inoculating” the people joining in on the thread that we will be disputing the misstatement and then later providing actual scientific information; and offering people on the thread the ability to take their own actions to find out what the scientific evidence says rather than passively accepting what they have read from the original poster. Because social reinforcement is an important component to maintaining false health and science beliefs, we also explain that there are social groups that promote the scientific evidence rather than false beliefs. 

With a grant from the Robert Wood Johnson Foundation we plan to test our protocol on drinking water safety and to find out if it is effective in persuading people who go online seeking information about the safety of drinking water in their community where there is sufficient useful scientific evidence that can be applied to the topic. We hope to dissuade people from unnecessarily purchasing bottled water or expensive home water filters when the water from their taps is perfectly safe to drink. Once we have learned what parts of our protocol work and what parts need adjustment, we hope to apply it to other health topics, including fears about a hopefully forthcoming coronavirus vaccine.

Jack Gorman is a physician and scientist who majored in English literature at Penn and now works as a behavioral healthcare improvement consultant in addition to serving as president of Critica. 

David Scales MD, PhD is the Chief Medical Officer for Critica and an assistant professor of medicine at Weill Cornell Medical College. David is an internist and hospitalist in New York City who did his undergraduate work at Penn and holds a PhD in sociology from Yale.

Cody Leff is a designer and software engineer specializing in user experience and data visualization for the web.  Cody received a B.S. in Architectural Design from Stanford University in 2015 and has since worked in a variety of technology-focused roles including product strategy, visual and experience design, software development, and digital marketing.  As part of the Critica team, Cody works to promote evidence-based decision-making for health and public policy issues through software and information technology solutions.

Sara Gorman is a public health specialist and author who has written extensively about mental health, global health, and the intersection of public health and psychology, among other topics. Sara’s book, Denying to the Grave: Why We Ignore the Facts That Will Save Us, published by Oxford University Press in 2016, explores the psychology behind irrational health beliefs and decisions. She is currently working on a second edition of the book covering the political war on science in the U.S. and the emergence of misinformation in the face of health crises such as COVID-19. Sara’s work has appeared or been reviewed in TIME, The New Yorker, Science, Psychology Today, The Atlantic, BBC, NPR, and Quartz. Sara majored in English at Penn, holds a PhD from Harvard, and an MPH from Columbia University Mailman School of Public Health.

Why Is Misinformation So Appealing?

What we know about misinformation in times of crisis.

It is a common experience to find things on the internet we might not have been expecting. For me, a catnip toy in the shape of Putin that I discovered in the winter of 2017 was certainly a highlight. 

But some discoveries are not nearly so pleasant. Lately, in the context of the coronavirus pandemic, there have been many of these not-so-pleasant internet discoveries. Among them were the short film “Plandemic,” a viral video that claimed, among other things, that masks activate the virus and that the coronavirus vaccine will kill millions of people. Then there is the ever-circulating conspiracy theory that Bill Gates created coronavirus so that he could use a vaccine to insert microchips in large portions of the American population that he would use to track people. 

While all of these claims are probably more widespread than they should be, there are also a series of other pieces of misinformation about the novel illness that are less extreme. For example, many people still believe that masks are ineffective against the virus and that children are unable to become ill from it. It is understandable why people would believe these misinformed tidbits, especially given statements made by usually reliable sources earlier in the pandemic. 

No matter how you look at it, misinformation and conspiracy theories are spreading at alarming rates. This has led the World Health Organization (WHO) to declare an “infodemic.” And indeed, a recent survey of US residents found that 23 percent believed that the virus was created intentionally (only 6 percent subscribed to the belief that it was created accidentally in a laboratory). With misinformation already on the rise and views about coronavirus becoming increasingly politicized, throwing a national election into the mix will likely only exacerbate things, accelerating politicization of false claims about the illness and making it more tempting to believe whatever best aligns with our increasingly passionate political views. 

While most of us probably have not seriously engaged with conspiracy theories such as the one about Bill Gates, many, many people are falling victim to false information about the transmission and treatment of the illness that turn out to be extremely dangerous—like believing that silver can cure the illness or that dark skin protects people from becoming infected. 

Marta DM/Shutterstock
Source: Marta DM/Shutterstock

So why is misinformation so appealing during times of crisis? Well, there are at least a few relatively simple explanations. One is that people are abnormally anxious during times of crisis. This is understandably the case. People who suffer from anxiety disorders will tell you that when you are extremely anxious, the desperate search for reassurance can lead you down some strange paths.

This is what is behind the dreaded “internet rabbit hole,” in which a panicked state of mind might lead you to conclude something bizarre based on how your anxiety is guiding your internet search. A lot of this has to do with the fact that the reasoning parts of your brain do not work quite as well when you’re highly anxious so you aren’t able to evaluate information as clearly.

There is also the related issue of distraction. The more distracted we are, the more likely we are to believe false claims. Having a lot of anxiety is like living in a constant state of distraction—it is as though there is a thin veil over everything we see and we can only barely make out what it is. 

But this can’t be the whole story, especially with claims that are especially unbelievable, like the idea that saltwater cures coronavirus. This is where we need to understand that people are not only having increased difficulty processing information but they also have a desire to believe something, anything. In order for misinformation to truly work its magic, there has to be a willingness on the part of the recipient (or victim) of misinformation to believe it.

You might be thinking: Why would we want to believe things that aren’t true? Well, extreme circumstances will create an opportunity for us to want this. In the case of something like the coronavirus pandemic, we have few definitive answers to our questions. Why did this happen? How do we stop it? How long will it take to stop it? We do have some answers to these questions but nothing is absolute in such a continuously evolving situation. Human beings are so uncomfortable sitting with this gap in knowledge that they would rather fabricate truth than just live with not knowing.

This is not to say we do this with everything. If there’s a topic I don’t know about, like how to fix a washing machine, but it doesn’t matter that much to me that I don’t know about it, then I am happy to just say “I don’t know.” But if the topic is somehow particularly salient and important and I’m not getting the answers I want from mainstream or typical sources, I will start to perform that panicked late-night internet search that leads me to strange, but oddly passable, explanations. 

Given this surge of misinformation, is there anything we can do to lead people to the correct information? It is certainly more complex than simply providing corrective information, but there is a whole literature suggesting various methods to fight misinformation. Here are a few highlights:

  1. Beware the continued influence effect. The continued influence effect refers to a phenomenon in which people hold on to debunked information even after it has been corrected. It is posited that this happens because people build a mental model explaining a particular series of events and it is difficult to disrupt this once it has been formulated. There are a few techniques that have been shown to help overcome this. One is to provide alternative explanations, rather than simply debunking information and saying it is wrong. This helps people build a new mental model. Another potentially effective technique is to warn people about the continued influence effect before you debunk the misinformation. In some cases, this awareness helps people engage more actively in displacing the debunked information. 
  2. Use both topic and technique rebuttal. Just as vaccines work by exposing people to small amounts of inactivated virus in order to mount an immune response, it is thought to be the case that a similar type of “inoculation” might work to debunk misinformation. That is, warning people that you are about to debunk incorrect information (topic rebuttal) or that you are about to question the methods by which that incorrect information was created (technique rebuttal) may be more effective in persuading people to believe the correct information than simply providing the corrective information on its own. 
  3. Use motivational interviewing techniques. The jury is still mostly out on this technique as a tool to counteract misinformation, but there is reason to believe that engaging people in an empathic dialogue about how they arrived at their views might help them be more open to hearing other sides of the story. This technique requires time and patience, as it may not be effective over the course of a single encounter.

The spread of misinformation surrounding COVID-19 is alarming and dire, but it is also understandable given high levels of stress and uncertainty. All we can do is continue to test new methods of debunking misinformation and continue to suggest techniques for managing anxiety in this highly unusual time. 

Evidence and Rumor

Making Sense of Treatments Claimed to Prevent or Treat COVID-19

Claims abound throughout traditional and social media about supposed treatments that allegedly can prevent or treat COVID-19. Common sense dictates that not all of these claims are true, but how does one sift through all the drugs, vitamins, minerals, and devices that are said to thwart the virus that causes COVID-19, SARS-CoV-2?

         Usually, we await the results of at least one large randomized controlled trial (RCT) (ore on what this is later) before accepting that a new treatment is likely to be safe and effective. For any drug or device that is explicitly aimed at treating a specific disease(s), this is generally what the US Food and Drug Administration (FDA) requires for approval. There are many supplements, medical foods, and “alternative” treatments that do not advertise a benefit for a specific disease but rather claim to improve some aspect of health, like “boosting” the immune system or improving memory. These drugs are not regulated by the FDA, but healthcare professionals and scientists still usually demand that rigorously conducted RCTs be completed before they will recommend them to their patients.

         These are, however, not ordinary times. The coronavirus pandemic is a health emergency and it may not be advisable to wait the years it can take for the most definitive studies to be completed for a putative new treatment. As the virus spreads, leaving in its wake death, disability, emotional turmoil, and a ruined economy, we are looking for quick solutions whenever possible. Anything that just might help is going to get attention in the form of press releases from medical schools and pharmaceutical companies, stories in newspapers and broadcast media, and posts on websites and social media. These can sometimes exaggerate the potential benefits of a new treatment or, worse, obscure its potential harms. On the other hand, these communications alert us that something is out there that might work.

         Vitamin D is a good case in point. Vitamin D has been touted as potentially both lowering the risk to be infected with the COVID-19 virus and reducing mortality among those infected. This has led a lot of people to take vitamin D supplements, hoping to prevent being infected with the novel coronavirus. Yet to date there are noD completed, published RCTs demonstrating that vitamin D either lowers the risk of getting infected or improves outcomes if one gets infected. So what is the basis for vitamin D and COVID-19 and how does one decide whether to take extra vitamin D during the pandemic? Let’s review three things: first, what exactly is vitamin D; second, what is the difference between an observational study and a randomized controlled trial; and third, how strong is the evidence that vitamin D plays a role in COVID-19?

Vitamin D Biology

         Vitamin D is a fat-soluble vitamin (meaning that unlike water-soluble vitamins, the body can store vitamin D) that was discovered in 1922 by Sir Edward Mellanby in Great Britain. Severe vitamin D deficiency leads to a serious weakening of bones and impaired walking, a condition called rickets. The main source of vitamin D is the sun, although it is also found at fairly low levels in some foods like fortified milk. As ultraviolet radiation from the sun hits the skin it causes a reaction that produces vitamin D. But this molecule must be converted in two steps to be active, first in the liver and then by the kidney. Its most obvious role is to increase the absorption of calcium from the gastrointestinal tract into the bloodstream, thus making calcium available for bone strength and health. Without sufficient vitamin D, there is insufficient calcium and bones get weaker.

Our main source of vitamin D is from the sun. It is also found in fairly levels in some foods and fortified milk and of course in supplements (source: Shutterstock).

         In addition to its importance for bone health, vitamin D is also known to modulate immune function and reduce inflammation, and this is the basis for believing it might be involved in COVID-19. Vitamin D has been implicated to play a role in a variety of other conditions, including respiratory diseases, cancer, and diabetes.

         It has been remarkably difficult to set upper and lower blood level limits for vitamin D or its active metabolite, in part because there is so much variability between different tests and in part because it has been very hard to figure out exactly what blood level is associated with good health. We know the level below which rickets can occur, but this condition is rare in medium- and high-income countries like the U.S.: most Americans get at least enough vitamin D to prevent rickets. We also have pretty good information about blood levels above which serious adverse outcomes occur, most notably too much calcium in the blood which can clog arteries and cause heart and kidney damage. How much is good for the heart, lungs, immune system, and other organs, however, is in dispute. This means that there are reasonable differences of opinion about how much vitamin D people should get every day, either from sun, foods, supplements or some combination of these. The current recommendation is 600 International Units (IU) for people aged one to 70 and 800 IU for people over 71, but some experts think more is needed for optimal health. The safe upper daily limit for adults is 4,000 IU. That leaves a lot of room between what is generally recommended and what people can tolerate, opening up the question of how much we really need.

The Difference Between Observational and Randomized Controlled Studies

         We mentioned above that the gold standard for evaluating the benefits and risks of any new drug or device is the randomized controlled trial (RCT), but this is not the only kind of informative research study. Many important findings emerge from observational studies, which sometimes can be done more quickly than RCTs. In a case like the vitamin D story, an observational study was done by researchers at the University of Chicago in which they looked at medical records of more than 4,300 people who had been tested for COVID-19 and found that of 499 of them who had vitamin D levels recorded before the pandemic, people who were “likely” vitamin D deficient were 77% more likely to get infected with SARS-CoV-2.

         This study is called observational because the experimenters did not control any aspect of what happened, they observed how many people got infected and their vitamin D levels and found an association between them. This is very important information, but there are two important things to remember about observational studies. First, because the experimenters don’t control anything, other variables that were unmeasured in the study could also be causing the apparent link between vitamin D and coronavirus infection. For example, perhaps poor people have less access to healthcare and live in more crowded conditions and also have less access to fortified milk. Anyone of those three things (plus many others) could be the reason for the group to have higher rates of infection. The study did not report on income, healthcare access, or living conditions and if any of these were the real reason for the higher risk of getting infected, then giving someone vitamin D would probably not help them.

         And second, because of this issue of unmeasured variables, observational studies only indicate associations between two or more things but cannot establish cause and effect. There is an association between height and weight: taller people generally weigh more than shorter people, but one does not cause the other (that is, separate processes determine how tall a person weighs and how tall they are). In other words, the Chicago study does not tell us whether low vitamin D levels actually cause a person to be at higher risk to get COVID, but it does suggest it might be the case.

         The only way to be sure that vitamin D actually causes the problem would be to randomly assign people in a study to receive either vitamin D or a placebo and then see how many in each group either get infected or, if already infected, survive. If the group that gets vitamin D does better than the placebo group, we have evidence of a causal relationship. Because in such a randomized study the only difference between groups is who gets vitamin D, we can rule out all other variables as being the cause of risk of infection.

         But RCTs have their problems too. First, in order to get people in each group who are the same on everything except whether they get vitamin D, researchers often have to exclude a lot of people who have situations or conditions that might bias the results. Therefore, RCTs are restricted to people who meet study requirements and may not give an accurate portrayal of who actually would benefit from vitamin D, assuming it beats placebo. Because observational studies do not usually exclude anybody from the study, they are more generalizable. Second, RCTs are very expensive and take a long time to complete. In a situation like the pandemic, we really don’t want to wait for a definitive answer if solid observational data suggest something might save lives.

Randomized clinical trials are considered the gold standard for determining if a new treatment is safe and effective, but in order to keep the intervention and non-intervention groups very similar, many people are disqualified from participating at the eligibility stage, making the trial results limited in generalizability (source: Schulz KF, Altman DG, ((Moher D; for the CONSORT Group)) (2010). “CONSORT 2010 Statement: updated guidelines for reporting parallel group randomised trials”. Br Med J. 340: c332).

The Vitamin D Story

         There are several parts to the story of a possible role for vitamin D in COVID in addition to the University of Chicago study described above. First, it is known that people with dark skin are less able to convert sunlight into vitamin D and it is clear that people of color have higher rates of infection and higher mortality rates when infected than do white people. However, there are of course a host of other reasons why this may be the case, including crowded living conditions, lack of access to healthcare, and higher rates of pre-existing medical conditions.

         Second, vitamin D is known, as mentioned earlier, to have a variety of effects on the immune system. One of these is an anti-inflammatory effect, which could conceivably be important in reducing the hyperactive immune response (sometimes referred to as “cytokine storm”) that appears to increase symptom severity in some patients with COVID-19. Thus, there is a plausible biological basis for thinking that vitamin D deficiency may be involved in COVID-19 and that vitamin D treatment might be helpful.

         Third, there are other observational studies that link “deficient” levels of vitamin D to risk and mortality associated with COVID-19, although some of them are “pre-prints”—articles that are posted online before they have been peer reviewed for publication in a journal (for example this study).

         In the face of this, however, are at least two observational studies that did not find any association between vitamin D deficiency and COVID-19.

         If all of this sounds confusing, you can perhaps take some solace in knowing that it is confusing experts in the fields of endocrinology, infectious diseases, and immunology as well. The UK National Institute for Health and Care Excellence (NICE) opined at the end of June that there is insufficient evidence to recommend vitamin D supplementation for any respiratory infection. On the other hand, six medical societies, while again insisting that “The current data do not provide any evidence that vitamin D supplementation will help prevent or treat COVID-19 infection,” still released a statement advocating that people get at least 15 to 30 minutes of sun every day (while taking steps to avoid sunburn) or, if that is not possible because of quarantine, stay-at-home, or other factors, taking vitamin D supplements.

         All of these statements make the point that we don’t have definitive clinical trial evidence that vitamin D supplementation will help prevent or treat COVID-19 and we have mixed observational evidence that vitamin D deficiency is involved in increasing risk or severity of illness. We would rather not waitfor big RCTs to be done on the one hand while on the other we don’t want to take things that don’t work and may even be harmful. What can we say about vitamin D, then?

         First, almost everyone agrees that people who are really vitamin D deficient should take a supplement, so people at increased risk for COVID-19 or who are already infected might do well at least to have a blood level determined.

         Second, there doesn’t seem to be any harm in following the recommendation to get 15 to 30 minutes of sun exposure every day (but be careful not to get sunburned and increase your risk for skin cancer). Remember, however, that this is just our read of the conflicting literature and recommendations; we are not in a position to offer anyone medical advice.

         The hardest thing of all is to know what to do about taking a supplement even if you don’t have a clear vitamin D deficiency. If you can’t get outside every day, perhaps the six medical society statement “that most adults 19 years and older obtain between 400-1000 International Units (IUs) of vitamin D daily from food and/or with supplements (ideal intake depends on age and sex)” is a reasonable course. Bear in mind, however, that there are significant adverse consequences of taking too much vitamin D. If you can still get vitamin D supplements, don’t gulp them down indiscriminately.

         The vitamin D situation illustrates a problem we all have during a health emergency. Balancing the need to use potentially life-saving interventions as quickly as possible with ensuring that those interventions actually work and cause no harm is not an easy task under ordinary circumstances; it is even harder during a pandemic. The press and social media will pick up on every even remote possibility and often give the impression that things are settled science. Upon further review by scientists, what seems like the latest breakthrough often loses some of its shine. Our job at Critica is to try to help you through these complexities so you at least have a broad enough range of information to be able to make your own, informed decisions.