Relative risk of incident heart failure or death, as a combined outcome, within 90 days of follow-up from admission to hospital for new onset myocarditis in individuals aged 12-39 years, with no predisposing comorbidities, and with myocarditis associated with SARS-CoV-2 mRNA vaccination, myocarditis associated with covid-19 disease, or conventional myocarditis
| Type of myocarditis | Diagnosis of heart failure or death (No of patients) | Total No of individuals | Relative risk (95% CI) of diagnosis of heart failure or death |
| Vaccination | 6 | 326 | 0.50 (0.22 to 1.12) |
| Covid-19 | 5 | 47 | 2.87 (1.23 to 6.70) |
| Conventional | 114 | 3077 | 1 (ref.) |
CI=confidence interval.