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 … Continue reading New JAMA Study on 23 million People Shows increased risk of myocarditis due to the jab