Phorum.com.gr

From analysis of UK and international data, there has been a signal of an increase of cases of myocarditis and pericarditis following vaccination with both Pfizer/BioNTech and Moderna vaccines. The Pfizer/BioNTech and Moderna vaccines have been used extensively in other countries, including the US and Israel.

In the US, 296 million doses of mRNA vaccines (Pfizer/BioNTech and Moderna) had been given by 11 June with 1,226 reports of myocarditis after vaccination (the US data analysis has included all cases of myocarditis, pericarditis and myopericarditis under myocarditis). In those with reported myocarditis, the median age was 26 years and the median time to onset was 3 days after the vaccination.

In Israel, between December 2020 and May 2021, there were 148 reports of myocarditis around the time of vaccination, with 5,401,150 individuals having received at least 1 dose of vaccine and 5,049,424 having received 2 doses. There have been higher incidences in younger males, and most cases reported after the second vaccination.

In the US, among those 1,194 individuals with myocarditis for which age was known, 687 were aged under 30 years, for those 1,212 individuals for which sex was known, 923 were male, and for those 1,094 individuals for which number of vaccine doses is known, 76% of cases developed myocarditis after dose 2. Reporting rates were 40.6 cases per million second doses of mRNA COVID-19 vaccines for males aged 12 to 29 years and 2.4 per million second doses for males aged 30 or older. For females their reported rates were 4.2 and 1.0 per million second doses in these age groups and the highest reporting rates were among males aged 12 to 17 and those aged 18 to 24 years. In Israel, 27 of the 148 cases occurred around receipt of the first vaccine dose and 121 occurred within 30 days after the second vaccine, with most cases in men aged 16 to 19 years.

Cases of myocarditis and pericarditis have been reported in the UK following vaccination with COVID-19 vaccines.

As of 28 July 2021, in the UK there were 149 reports of myocarditis and 129 reports of pericarditis following use of the Pfizer/BioNTech vaccine, 82 reports of myocarditis and 140 reports of pericarditis following use of the AstraZeneca (AZ) vaccine, and 25 reports of myocarditis and 22 reports of pericarditis following use of the Moderna vaccine.

The overall rates after both the first and second doses of Pfizer/BioNTech are 4.3 myocarditis cases per million doses and 3.8 pericarditis cases per million doses, for AZ the rate is 1.7 myocarditis cases per million doses and 3.0 pericarditis cases per million doses, and for Moderna the rate is 14.7 myocarditis cases per million doses and 13.0 pericarditis cases per million doses.

Up to 28 July 2021, 20.46 million first doses and 13.8 second doses of the Pfizer/BioNTech have been administered, 24.8 million first doses and 23.6 million second doses of the AZ vaccines and 1.3 million first doses of the Moderna vaccine have been administered. Given the extensive use of AZ vaccine in the UK programme, the cases reported after AZ vaccine are thought to reflect the expected background rate of these conditions.