National Cohort Comparison of COVID-19 mRNA Vaccine Injury---Risks Real but Rare, COVID-19 Infection Not Relevant

Researchers from National Taiwan University and its hospital along with the Centers for Disease Control under its Ministry of Health and Welfare investigated rates of myocarditis and pericarditis associated with mRNA COVID-19 vaccines. This systematic, quasi-meta-analysis was conducted because although early clinical trials indicated low incidence, according to the study authors, they also found substantial variation across studies. Their key hypothesis: study characteristic, ethnicity, vaccine type, dose intervals and COVID-19 prevalence in particular community or nation may influence the rates of the endpoint: myocarditis and pericarditis post mRNA vaccination in population-based cohort studies. Tapping into MEDLINE, and other relevant content published up till November 30, 2022, the team also scoured websites for unpublished surveillance data covering the targeted conditions linked to mRNA vaccination. The key question for this study: incidence of myocarditis and pericarditis post COVID-19 vaccination  with study investigator interest in determining if previous COVID-19 infection and young Asian males represented risk factors.

Corresponding author Chia-Hsuin Chang, M.D. a specialist in Endocrinology, Diabetics and Metabolism at National Taiwan University Hospital, Department of Internal Medicine and colleagues initially looked at 327 studies but had to exclude 301 of them because they were case reports, case series, and cohort studies in which the participants were not taken from the general population. Ultimately, 17 studies from 10 nations were included in the meta-analysis.