New Heart Disease Diagnosis After COVID-19 Vaccination Very Rare

Recent studies^1,2 have suggested a possible association between the mRNA COVID-19 vaccination and myocarditis, an inflammation of the heart muscle. The CDC is actively reviewing rare reports of post-vaccination myocarditis, especially in adolescent males.³

We studied 15 million patients who were vaccinated between December 11, 2020 and June 9, 2021 and found 291 cases where patients were newly diagnosed with myocarditis within 30 days of receiving the vaccine, for a rate of 19.4 per million patients.

Figure 1

To contextualize these findings with historical baselines, we counted the number of patients with an encounter with a new diagnosis of myocarditis within 30 days after an office visit in 2019. We found a rate of 14.5 new diagnoses of myocarditis per million patients, meaning that the incidence of myocarditis following the COVID-19 vaccine is not substantively different from historical risk rates.

These data come from Cosmos, a HIPAA-Limited Data Set of more than 119 million patients from 141 Epic organizations including 832 hospitals and 13,421 clinics, serving patients in all 50 states. This study was completed by two teams, each comprised of a clinician and research scientists who worked independently. The two teams came to similar conclusions.

References

1. Montgomery J, Ryan M, Engler R, et al. Myocarditis Following Immunization With mRNA COVID-19 Vaccines in Members of the US Military. JAMA Cardiol. Published online June 29, 2021. doi:10.1001/jamacardio.2021.2833
2. Kim HW, Jenista ER, Wendell DC, et al. Patients With Acute Myocarditis Following mRNA COVID-19 Vaccination. JAMA Cardiol. Published online June 29, 2021. doi:10.1001/jamacardio.2021.2828
3. Centers for Disease Control. Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination. CDC: COVID-19. Last updated June 23, 2021. Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination | CDC