Analysis of Myocarditis Among 252 Million mRNA-1273 Recipients Worldwide

Abstract

Background Growing evidence indicates a causal relationship between SARS-CoV-2 infection and myocarditis. Post-authorization safety data have also identified myocarditis as a rare safety event following mRNA COVID-19 vaccination, particularly among adolescent and young adult males after dose 2. We further evaluated the potential risk by querying the Moderna global safety database for myocarditis/myopericarditis reports among mRNA-1273 recipients worldwide. Methods Myocarditis/myopericarditis reports from December 18, 2020, to February 15, 2022, were reviewed and classified. The reported rate after any known mRNA-1273 dose was calculated according to age and sex, then compared to a population-based incidence rate to calculate observed-to-expected rate ratios (RR). Results During the study period, 3017 myocarditis/myopericarditis cases among 252 million mRNA-1273 recipients were reported to the Moderna global safety database. The overall reporting rate was 9.23 per 100,000 person-years, which was similar to the expected reference rate (9.0 cases per 100,000 person-years; RR [95% CI], 1.03 [0.97-1.08]). When stratified by sex and age, observed rates were highest for males aged <40 years, particularly those 18-24 years (53.76 per 100,000 person-years), which was higher than expected (RR [95% CI], 3.10 [2.68-3.58]). When considering only cases occurring within 7 days of a known dose, the observed rate was highest for males aged 18-24 years after dose 2 (4.23 per 100,000 doses administered). Conclusion Myocarditis/myopericarditis rates were not higher than expected for the overall population of mRNA-1273 recipients but were higher than expected in males aged 18-24 years, with most cases occurring 7 days after dose 2.

Incidence and risk factors of myocarditis in hospitalized patients with COVID‐19

“…Remarkably, the in‐hospital case‐fatality rate of COVID‐19 patients with myocarditis increased substantially with age. This age‐dependency of myocarditis in COVID‐19 patients was also seen for myocarditis in the general population 10,14,30 of other studies as well as postvaccination myocarditis 19,28,31–35 . Significantly young male individuals were affected by myocarditis after SARS‐CoV‐2‐vaccination 33,34 .…”

“…This agedependency of myocarditis in COVID-19 patients was also seen for myocarditis in the general population 10,14,30 of other studies as well as postvaccination myocarditis. 19,28,[31][32][33][34][35] Significantly young male individuals were affected by myocarditis after SARS-CoV-2vaccination. 33,34 The observation of our study strengthens the hypothesis that younger COVID-19 patients have a higher risk of developing a myocarditis, but myocarditis has a higher harmfulness in older patients with COVID-19.…”

“…19,28,[31][32][33][34][35] Significantly young male individuals were affected by myocarditis after SARS-CoV-2vaccination. 33,34 The observation of our study strengthens the hypothesis that younger COVID-19 patients have a higher risk of developing a myocarditis, but myocarditis has a higher harmfulness in older patients with COVID-19.…”

Emerging heterologous mRNA-based booster strategies within the COVID-19 vaccine landscape

“…Although not described within publications from this search, rare cases of myocarditis and pericarditis have been reported after the administration of mRNA-1273 or BNT-162b2. 112 , 113 In particular, rates of myocarditis in mRNA-1273 vaccine recipients were not higher than expected for the general population, with the exception of males aged 18–24 years.…”

Vaccine‐Triggered Acute Autoimmune Myocarditis: Defining, Detecting, and Managing an Apparently Novel Condition

“…Reviewing the literature is to be done with caution: the many published case reports and series inevitably include reporting bias, and the several systematic reviews 10 , 11 , 12 , 13 draw from the same pool of published cases, creating a sort of repetition bias. Other sources include safety surveillance, 14 , 17 insurance claims, 18 and national registry databases; these are also likely to underreport milder cases, and a truer disease representation will likely include greater incidence with lower severity. Nonetheless, the consistency of clinical features, across these different data sources, is striking; typically, ≈90% are male, with a median age somewhere in the 20s (depending on age groups vaccinated).…”