How to Express Risk in the Headlines

Two headlines on the same topic appeared recently, conveying very different messages about health risk. The first appeared in an online source called MEDPAGE TODAY on October 6. It read:

Israeli Data Favor Higher Estimates of Post-Vax Myocarditis.

The second appeared in the Israeli newspaper Haaretz the next day and read:

Study: Only 142 Out of 5 Million Vaccinated Israelis Suffered Heart Inflammation

         Both headlines, and the stories they accompanied, are reporting on studies that appeared in the New England Journal of Medicine that looked at the incidence of a type of inflammation of the heart muscle, called myocarditis, and its incidence after receiving the Pfizer/BioNTech COVID-19 vaccine.

         The actual research studies about post-vaccination myocarditis are generally felt to be important contributions to our understanding of the risks and benefits of COVID-19 vaccines and they generally paint a reassuring picture about vaccine safety. Stories in the media about this research, however, vary substantially in the amount of concern they are likely to cause among a reading public. The headline from MEDPAGE TODAY, admittedly intended for a medical audience, creates the impression that something new and dangerous has been discovered about the vaccines. One might infer from this headline that previously low rates of myocarditis attributed to the vaccines were wrong and that new research has revealed a much more significant problem. The Haaretz headline, by contrast, puts this new information immediately in context: only 142 cases of myocarditis out of 5 million people who received a COVID-19 vaccine, for an incidence of 0.003% or around 1 case of myocarditis in every 35,000 or so people vaccinated.

         We can put this into even further perspective by looking at the two papers in the New England Journal of Medicine about which these stories are reporting. Both were studies from Israel that looked at rates of myocarditis following the Pfizer/BioNTech COVID-19 vaccine. Both found very small rates of myocarditis after receiving the vaccine, and both found that the risk was highest in teenage boys and young men. And finally, both studies found that myocarditis post-vaccination was almost always mild or moderate and resolved without any further consequences.

What Is Myocarditis

         Myocarditis  is an inflammation of the heart muscle, or myocardium, that occurs in about 1.5 million people worldwide every year, with an incidence of at least 10 to 20 cases per 100,000 people. Most cases are caused by viruses, although there are a number of other causes. The symptoms are usually not subtle and include relatively sudden onset of chest pain, difficulty breathing, and fatigue. Jack Gorman, the Critica president, remembers that the first patient he admitted to the hospital when he was an intern in pediatrics at a New York City hospital in July, 1977 was a young man with myocarditis. The patient was in very mild distress, his admission to the hospital was precautionary, and he recovered uneventfully. That is the typical course of myocarditis, although it can be more serious and in one of the New England Journal of Medicine studies there was one death from post-vaccination myocarditis.

Myocarditis is a disease in which the heart muscle or myocardium becomes inflamed. The most common cause of myocarditis is viral infection (image: Shutterstock).

As explained in an excellent article in the journal Nature, the risk of myocarditis from actual COVID-19 infection is 18 times the annual incidence rate cited in the paragraph above, “a much more significant risk than is observed following vaccination.” Because the rate is a bit higher among young men, some governments have decided not to authorize mRNA vaccines (that is, the Pfizer/BioNTech and Moderna/NIH vaccines) to that group of people. The article in Nature explains that the risk in teenage boys and young men “of developing myocarditis might be increased more by the vaccine than by the disease, particularly because children rarely develop severe COVID-19.” In all other demographics, the risk of getting myocarditis from COVID-19 appears to be clearly higher than is the risk from the vaccine. Hence, with the possible exception of teenage boys and young men, the myocarditis data leave unchanged recommendations that most people should have a COVID-19 vaccine as soon as possible.

Putting the Myocarditis Risk in Perspective

The facts about post-vaccination myocarditis have not stopped anti-vaccination advocates from using the Israeli studies to bolster their argument that the COVID-19 vaccines are dangerous. This is curious at best because they often cite as a reason against vaccination what they claim to be a 99% survival rate from COVID-19. That means, of course, that they believe that 1% of us–one out of every 100 people–infected with the virus that causes COVID-19 will die. Isn’t that a much greater risk than the 0.003% or around 1 case of myocarditis out of every 35,000 people, especially given the fact that almost all of those people with myocarditis recover and death from post-vaccination myocarditis is very rare?

What concerns us most, however, is not anti-vaccination misinformation but rather the fears that can be stoked by misleading headlines.  The excellent headline in Haaretz about post-vaccination myocarditis immediately puts it into context and the rest of the story tells us that while there is a concern about vaccinating young men (whose risk is still very, very low of developing a serious problem), people can be reassured that once again very careful surveillance and data analysis proves the COVID-19 vaccines to be remarkably safe. Not all headlines we saw, however, were this careful and responsible and some, obviously trying to entice readers to “click,” implied a much more serious problem.

The Haaretz headline shows us that it is perfectly possible to keep the public informed about the latest scientific developments without scaring us. Do editors and journalists worry that a headline or story that tells us that a health risk is exceedingly small won’t attract readers? Perhaps. But we are hopeful that editors and journalists understand that they have a huge impact on the public’s health and that nuance in their headlines and stories have great potential to affect our attitudes and our behaviors. Editors and journalists know that it is a public health imperative that as many people as possible get vaccinated against COVID-19. That means crafting their messages carefully so that they convey the best possible public health messages. This applies not only to stories about COVID-19 vaccines, but to all stories about health and science in which our safety is at stake.

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