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Meta-Analysis
. 2023 Jun 20;13(6):e065687.
doi: 10.1136/bmjopen-2022-065687.

Risk of myocarditis and pericarditis in mRNA COVID-19-vaccinated and unvaccinated populations: a systematic review and meta-analysis

Abdallah Alami  1 , Daniel Krewski  2   3 , Nawal Farhat  4 , Donald Mattison  2   3   5 , Kumanan Wilson  6   7 , Christopher A Gravel  2   8   9 , Patrick J Farrell  4 , James A G Crispo  10   11 , Nisrine Haddad  2 , Santiago Perez-Lloret  12   13   14 , Paul J Villeneuve  15
Affiliations
Meta-Analysis

Risk of myocarditis and pericarditis in mRNA COVID-19-vaccinated and unvaccinated populations: a systematic review and meta-analysis

Abdallah Alami et al. BMJ Open. .

Abstract

Objective: To summarise the available evidence on the risk of myocarditis and/or pericarditis following mRNA COVID-19 vaccination, compared with the risk among unvaccinated individuals in the absence of COVID-19 infection.

Design: Systematic review and meta-analysis.

Data sources: Electronic databases (Medline, Embase, Web of Science and WHO Global Literature on Coronavirus Disease), preprint repositories (medRxiv and bioRxiv), reference lists and grey literature were searched from 1 December 2020 until 31 October 2022.

Study selection: Epidemiological studies of individuals of any age who received at least one dose of an mRNA COVID-19 vaccine, reported a risk of myo/pericarditis and compared the risk of myo/pericarditis to individuals who did not receive any dose of an mRNA COVID-19 vaccine.

Data extraction and synthesis: Two reviewers independently conducted screening and data extraction. The rate of myo/pericarditis among vaccinated and unvaccinated groups was recorded, and the rate ratios were calculated. Additionally, the total number of individuals, case ascertainment criteria, percentage of males and history of SARS-CoV-2 infection were extracted for each study. Meta-analysis was done using a random-effects model.

Results: Seven studies met the inclusion criteria, of which six were included in the quantitative synthesis. Our meta-analysis indicates that within 30-day follow-up period, vaccinated individuals were twice as likely to develop myo/pericarditis in the absence of SARS-CoV-2 infection compared to unvaccinated individuals, with a rate ratio of 2.05 (95% CI 1.49-2.82).

Conclusion: Although the absolute number of observed myo/pericarditis cases remains quite low, a higher risk was detected in those who received mRNA COVID-19 vaccinations compared with unvaccinated individuals in the absence of SARS-CoV-2 infection. Given the effectiveness of mRNA COVID-19 vaccines in preventing severe illnesses, hospitalisations and deaths, future research should focus on accurately determining the rates of myo/pericarditis linked to mRNA COVID-19 vaccines, understanding the biological mechanisms behind these rare cardiac events and identifying those most at risk.

Keywords: COVID-19; Epidemiology; PUBLIC HEALTH.

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Conflict of interest statement

Competing interests: KW is a co-founder and Chief Scientific Officer of CAN Immunize Inc. (www.canimmunize.ca). He served on the Independent Data Monitoring Committee for Medicago, and is a member of the Moderna Global Advisory Core Consultancy Group. DK serves as Chief Risk Scientist (www.risksciences.com) and has conducted work on vaccines for public sector clients.

Figures

Figure 1
Figure 1
Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow chart summarising the process to identify studies that met the eligibility criteria for inclusion in the systematic review.
Figure 2
Figure 2
Meta-analysis of the rate ratios (RR) of myo/pericarditis in vaccinated relative to unvaccinated individuals. DL, DerSimonian-Laird.
Figure 3
Figure 3
Rate ratio (RR) of myo/pericarditis in vaccinated relative to unvaccinated individuals by study setting. DL, DerSimonian-Laird.
Figure 4
Figure 4
Rate ratio (RR) of myo/pericarditis in vaccinated relative to unvaccinated individuals within 30 days after vaccination and among concurrently unvaccinated comparators. DL, DerSimonian-Laird.
See this image and copyright information in PMC

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