Researchers in Israel say they have found a possible link between the Pfizer-BioNTech COVID-19 vaccine and cases of heart inflammation in young men between the ages of 16 and 30, according to a report presented this week in the country Ministry of Health.
The report concludes that about 1 in 5,000 men who receive the vaccine may experience this side effect, known as myocarditis, which is higher than the percentage seen in the entire vaccinated population during this time period, which was 1 in 50 000.
So far, the data are not strong enough to prove that the vaccine caused these cases ̵
And even if there is a link, it is important to note that the majority of myocarditis cases seen after vaccination have so far been mild and have responded well to anti-inflammatory drugs, such as steroids, said Dr. Alejandro Jordan-Villegas. pediatric expert on infectious diseases at Orlando Children’s Health Hospital Arnold Palmer, who did not participate in the report. At this point, “the benefits of the vaccine outweigh the risks,” Jordan-Villegas told Live Science.
In fact, the US Centers for Disease Control and Prevention (CDC) continues to recommend the COVID-19 vaccine for all eligible groups, which includes anyone over the age of 12. And on Friday (June 4th), the CDC emphasized the importance of the vaccine for teenagers, who increased the number of hospitalizations with COVID-19 in March and April.
“I ask parents, relatives and close friends to join me and talk to teenagers about the importance of these prevention strategies and encourage them to get vaccinated,” said CDC Director Dr. Rochelle Valensky. said in a statement.
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The Israeli report, led by Dr. Dror Mevorah, head of internal medicine at the Hadassah Medical Center in Jerusalem, found more than 110 cases of myocarditis in Israel that occurred during the COVID-19 vaccination, mostly after the second shot from about 5 million people vaccinated nationwide. This results in up to 1 in 50,000 people vaccinated. But the majority of people who have developed myocarditis are young men, with the percentage of men between the ages of 16 and 24 (who make up 10% of the vaccinated population) estimated at 1 in 5,000, according to a report sent by Mevorach. by email to Live Science. However, younger men are generally more likely than women to develop myocarditis, according to the National Organization for Rare Diseases.
Data from one hospital, Hadassah Medical Center, also found that the incidence of myocarditis observed at the hospital in recent months was five to 25 times higher than that observed in previous years, the report said; the breakdown of cases by year as well as the age range of cases were not included in the report.
In response to the report, Pfizer stated that it was aware of the findings but that no causal link had been established between myocarditis and its vaccine, according to Reuters.
One difficulty in determining whether the COVID-19 vaccine is associated with myocarditis is that the actual percentage of myocarditis in the general population is unclear, Jordan-Vilegas said. Doctors estimate the rate is about 2 to 3 cases per 100,000 people a year, Jordan-Villegas said, but could be higher because the cases may be under-reported. (Emphasizing how difficult it is to understand the underlying prevalence of the condition, review in Journal of Cardiothoracic and Vascular Anesthesia estimates that the incidence of viral myocarditis is 10 to 22 cases per 100,000 per year.) This makes it difficult to say “whether it is really an increase or not,” he said of the findings in Israel.
Moreover, myocarditis itself is usually caused by a viral infection, in particular by viruses known as enteroviruses, Jordan-Vilegas said. And at this time of year – the summer months – doctors usually see an increase in enterovirus cases, he said, making it difficult to establish a link specific to the COVID-19 vaccine.
The Israeli report also does not include information on the incidence of myocarditis in the unvaccinated population, which would be necessary to show that the vaccine is likely to cause this symptom.
“This is not evidence, it’s just a signal that the phenomenon needs to be investigated,” said Dr. Eyal Leshem, director of the Center for Tourism Medicine and Tropical Diseases at Sheba Medical Center in Ramat Gan, Israel. The Jerusalem Post.
Still, the timing of myocarditis cases is interesting – most cases occurred within 1 to 5 days after the second shot, the report said, meaning the timing of patients’ symptoms doesn’t seem random. “These findings increase the likelihood of a causal link between the vaccine and myocarditis,” the report said.
In the United States, researchers have also observed increase in cases of myocarditis reported to the Adverse Vaccine Reporting System (VAERS), the country’s vaccine safety monitoring system that allows people to report health problems after vaccination. Recent VAERS data show a higher-than-expected number of myocarditis cases in 16- to 24-year-olds within 30 days of receiving their second shot from either the Pfizer or Moderna vaccine, according to CDC Advisory Committee on Immunization Practices (ACIP). But VAERS is not designed to find out if a vaccine causes an adverse event – anyone can report an event and the system does not compare the percentage of cases between vaccinated and unvaccinated people, which can help determine if the link is really causal.
Another, smaller vaccine monitoring system in the United States, called Vataline Safety Datalink (VSD), compares the incidence of adverse events between vaccinated and unvaccinated people in nine hospital systems. But so far, VSD has not shown a higher rate of myocarditis than expected, according to ACIP. However, “these data need to be monitored closely as more people in the younger age groups have been vaccinated,” ACIP said.
For now CDC advises parents and young people to be alert for symptoms of myocarditis, which include chest pain, shortness of breath, fatigue and a feeling of rapid beating, fluttering or heartbeat; they should seek medical attention if they have their children have these symptoms within one week of being vaccinated against COVID-19.
Originally published in Live Science.