An Israeli study: The chance of developing myocarditis following Pfizer vaccine is extremely rare

An Israeli study, the first of its kind in the world, which included hundreds of thousands of Pfizer vaccines, shows that the chance of developing myocarditis following the vaccine is extremely rare, and even when it is realized, it is a very mild disease, without affecting heart function. The study is published Thursday night in the leading medical journal The New England Journal of Medicine.
The study, conducted by the Beilinson Hospital Cardiology Department in collaboration with the Clalit Research Institute, examined the prevalence of myocarditis and its severity after receiving the first and second dose of the vaccine. Anonymous electronic records of 2.5 million Clalit insureds who received the Pfizer vaccine against the corona were analyzed. The study was conducted by Beilinson cardiologists led by Prof. Ran Kornowski and included the collection and analysis of information on each patient, including laboratory results, imaging and drug treatment from the moment of onset of the disease until about 12 weeks after discharge from the hospital.
The findings show that out of 2.5 million vaccinated people over the age of 16, only 54 had myocarditis up to 42 days after receiving the vaccine (51 of them men and three women). This is 2.13 cases for every 100,000 vaccinated. It was also found that the side effect appeared more after the second dose of vaccine (69%), among more men and more in the age group 16 to 29. In this group - men aged 29-16 - 10.7 cases of myocarditis per 100,000 vaccinated were found.
76% of patients (41) suffered from mild inflammation, with no evidence of myocardial infarction. 22% - 12 patients - suffered from moderate severity, which included mild symptoms with non-severe damage to the heart muscle. Only one patient had a serious illness.
Further analysis of the data found that in 71% of patients there was no sign of impaired cardiac function at any stage. In 29% of the other patients, in about 85% the injury was mild to moderate. In all but one case, cardiac function returned to normal within a short period of time.
In terms of the duration of the disease, it was found that the average duration of hospitalization was relatively short. With the exception of one case, of a patient in his 20s, whose condition deteriorated during hospitalization, and he needed resuscitation and was later connected to Acmo - the condition of the other patients remained completely stable during hospitalization.
"The study's findings show that myocarditis is a relatively rare side effect of the vaccine, even in young men who were considered at risk," says cardiologist Dr. Guy Whitberg of Beilinson. . We were pleased to find that of the few vaccinated who had myocarditis, the majority experienced a relatively mild illness and needed a short hospital stay. "
"These are significant results," added Prof. Kornowski, director of the Beilinson Cardiology Division. "Unlike previous work, which was based on data from specific hospitals, our findings included complete data from a vaccination operation in a national health system."
Prof. Ran Blitzer, director of the Clalit Research Institute, said: "The findings in this study complement Clalit's previous study, which showed that the rate of serious cardiac symptoms does not increase in vaccinated people - but increases in coronary heart disease patients. Not in the short and medium term either. "