The agency said it was still investigating the potential risk and had not yet reached a final conclusion on the cause-and-effect relationship between the vaccine and myocarditis and pericarditis.

More young men than expected had heart muscle inflammation after receiving a second dose of the Pfizer / BionTech Covid-19 mRNA vaccine, data from two vaccine monitoring systems showed last Thursday.

According to the US Centers for Disease Control and Prevention (CDC), the agency and other health regulators are investigating the issue of myocardial infarction after the Israeli Ministry of Health announced that it had discovered a possible link between this medical condition in younger men and vaccination with the Pfizer vaccine against covid-19.

The agency said it was still investigating the possible risk and had not yet reached a final conclusion on the cause-and-effect relationship between the vaccine and the occurrence of myocarditis and pericarditis.

"While some patients needed hospitalization, most recovered completely," the CDC said.

More than half of all cases of myocarditis and pericarditis in the US Vaccine Side Monitoring System after patients received a second dose of Pfizer / BionTech or Modern have occurred in people aged 12 to 24, according to the CDC. .

Less than 9 percent of vaccines are administered in that age group. „There really is an imbalance hereSaid Dr. Tom Shimabukuro, deputy director of the CDC's Center for Immunization Safety, in a presentation to the US Food and Drug Administration at a meeting on Thursday. Most cases occurred within a week of vaccination, Shimabukuro added.

According to the CDC, 283 cases of inflammation of the heart muscle have been reported after the second dose of the vaccine in people aged between 16 and 24, while between 10 and 102 cases were expected in this age group.

Shimabukuro stressed that the VSD system, another that monitors vaccine safety, found an increased incidence of myocarditis in the age group between 16 and 39 years after the second dose of the vaccine, compared with the percentage seen after the first dose.

The Israeli Ministry of Health has previously said it had found a possible link between the vaccine and the small number of cases of myocarditis in younger men who received the Pfizer vaccine.

The CDC said it would hold a meeting of the Immunization Advisory Board later this week to further analyze the evidence and assess the risk of myocarditis after vaccination with the mRNA vaccine against covid-19.

Pfizer said it supported the CDC analysis, but also stressed that the number of cases was very small, given how many doses of the vaccine had been used. An estimated 130 million people in the United States have received both doses of one of the mRNA vaccines.

"Moderna" announced that they have not found a connection between that heart condition and their vaccine, but that they are actively working with the representatives of the public health and with the regulators for further analysis of this issue.