A study was recently published analysing the short-term risk of developing myocarditis and pericarditis up to 28-days after administration of the 1st and 2nd doses of a covid vaccine in the Nordic countries. The results show that out of the 23m people surveyed, a total of 1077 myocarditis and 1149 pericarditis events were identified. For young males aged 16-24 years, the risk following the 2nd dose of Pfizer was 4 to 7 times the background rate and following the 2nd dose of Moderna that risk was in excess of 9 to 28 times.
SARS-CoV-2 Vaccination and Myocarditis in a Nordic Cohort Study of 23 Million Residents
Question Is SARS-CoV-2 messenger RNA (mRNA) vaccination associated with risk of myocarditis?
Findings In a cohort study of 23.1 million residents across 4 Nordic countries, risk of myocarditis after the first and second doses of SARS-CoV-2 mRNA vaccines was highest in young males aged 16 to 24 years after the second dose. For young males receiving 2 doses of the same vaccine, data were compatible with between 4 and 7 excess events in 28 days per 100 000 vaccinees after second-dose BNT162b2, and between 9 and 28 per 100 000 vaccinees after second-dose mRNA-1273.
Meaning The risk of myocarditis in this large cohort study was highest in young males after the second SARS-CoV-2 vaccine dose, and this risk should be balanced against the benefits of protecting against severe COVID-19 disease.