tl;dr: " Subgroup analyses by age showed that the increased risk of events associated with the two mRNA vaccines was present only in those aged under 40 years.

tl;dr: " Subgroup analyses by age showed that the increased risk of events associated with the two mRNA vaccines was present only in those aged under 40 years. For this age group, we estimated 2 (95% CI 1, 3) and 8 (95%CI 4, 9) excess cases of myocarditis per 1 million people receiving a first dose of BNT162b2 and mRNA-1273, respectively, and 3 (95% CI 2, 4) and 15 (95%CI 12, 16) excess cases of myocarditis per 1 million people receiving a second dose of BNT162b2 and mRNA-1273, respectively. This compares with ten (95% CI 7, 11) extra cases of myocarditis following a SARS-CoV-2 positive test in those aged under 40 years." "Vaccination for SARS-CoV-2 in adults was associated with a small increase in the risk of myocarditis within a week of receiving the first dose of both adenovirus and mRNA vaccines, and after the second dose of both mRNA vaccines. By contrast, SARS-CoV-2 infection was associated with a substantial increase in the risk of hospitalization or death from myocarditis, pericarditis and cardiac arrhythmia."