Comparative Risk of Myocarditis/Pericarditis Following Second Doses of BNT162b2 and mRNA-1273 Coronavirus Vaccines
Key result
Second-dose mRNA-1273 linked to ~178% higher myocarditis odds compared with BNT162b2.
- aOR 2.78
- 95% CI 1.67-4.62
- n=3,095,414
Why the study?
Postmarketing evaluations linked myocarditis to COVID-19 mRNA vaccines, but few population-based analyses directly compared the safety of BNT162b2 and mRNA-1273.
Does the mRNA-1273 COVID-19 vaccine increase the risk of myocarditis or pericarditis compared to the BNT162b2 vaccine in adults receiving their second dose?
Study Design
Type
Cohort (n=3,095,414)
Structured PICO
Does the mRNA-1273 COVID-19 vaccine increase the risk of myocarditis or pericarditis compared to the BNT162b2 vaccine in adults receiving their second dose?
P
Population
3,095,414 adults aged 18 years and older who received a second dose of an mRNA COVID-19 vaccine in British Columbia, Canada, followed for 21 days to assess the risk of myocarditis and pericarditis.
E
Exposure
Second dose of mRNA-1273 COVID-19 vaccine
C
Comparator
Second dose of BNT162b2 COVID-19 vaccine
O
Outcome
Diagnosis of myocarditis, pericarditis, or myopericarditis during a hospitalization or emergency department visit within 21 days following the second vaccination dosesafety
Main Result
Odds Ratio: 2.78 (95% CI 1.67–4.62)
Absolute Event Rate: 35.6% vs 12.6%
Limitations
- Observational nature limits ability to infer causality
- Residual confounding
- Unable to control for additional potential confounders such as geography
- Relied on hospital and emergency department visit data, potentially missing less severe events
- Outcome definition based on diagnostic codes with no chart reviews
- Small number of outcomes limits statistical power in some strata
- Observational nature limits the ability to infer causality
- Residual confounding may contribute to differences in outcome rates
- Inability to control for additional potential confounders such as geography due to rarity of events
- Reliance on hospital and emergency department visit data may have missed less severe events
- Outcome definition based on diagnostic codes with no chart reviews, potentially subjecting outcomes to misclassification
- Small number of outcomes limiting statistical power in some strata (e.g., older ages and women)
Ask about this paper
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Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“[The study] should help put to rest 'vaccine hesitancy' due to concerns over cardiac adverse events”
“Few population-based analyses have been conducted to directly compare the safety of the two mRNA COVID-19 vaccines, which differ in important ways that could impact safety. Our findings have implications for strategizing the rollout of mRNA vaccines, which should also consider the self-limiting and mild nature of most myocarditis events, benefits provided by vaccination, higher effectiveness of the Moderna vaccine against infection and hospitalization [found in prior studies], and the apparent higher risk of myocarditis following COVID-19 infection than with mRNA vaccination.”
Implication
The mRNA-1273 COVID-19 vaccine is associated with a significantly higher risk of myocarditis and pericarditis compared to BNT162b2, particularly in young men, which may inform future vaccine selection policies.
Abstract
Background Postmarketing evaluations have linked myocarditis to COVID-19 mRNA vaccines. However, few population-based analyses have directly compared the safety of the 2 mRNA COVID-19 vaccines. Objectives This study aimed to compare the risk of myocarditis, pericarditis, and myopericarditis between BNT162b2 and mRNA-1273. Methods We used data from the British Columbia COVID-19 Cohort (BCC19C), a population-based cohort study. The exposure was the second dose of an mRNA vaccine. The outcome was diagnosis of myocarditis, pericarditis, or myopericarditis during a hospitalization or an emergency department visit within 21 days of the second vaccination dose. We performed multivariable logistic regression to assess the association between vaccine product and the outcomes of interest. Results The rates of myocarditis and pericarditis per million second doses were higher for mRNA-1273 (n = 31, rate 35.6; 95% CI: 24.1-50.5; and n = 20, rate 22.9; 95% CI: 14.0-35.4, respectively) than BNT162b2 (n = 28, rate 12.6; 95% CI: 8.4-18.2 and n = 21, rate 9.4; 95% CI: 5.8-14.4, respectively). mRNA-1273 vs BNT162b2 had significantly higher odds of myocarditis (adjusted OR [aOR]: 2.78; 95% CI: 1.67-4.62), pericarditis (aOR: 2.42; 95% CI: 1.31-4.46) and myopericarditis (aOR: 2.63; 95% CI: 1.76-3.93). The association between mRNA-1273 and myocarditis was stronger for men (aOR: 3.21; 95% CI: 1.77-5.83) and younger age group (18-39 years; aOR: 5.09; 95% CI: 2.68-9.66). Conclusions Myocarditis/pericarditis following mRNA COVID-19 vaccines is rare, but we observed a 2- to 3-fold higher odds among individuals who received mRNA-1273 vs BNT162b2. The rate of myocarditis following mRNA-1273 receipt is highest among younger men (age 18-39 years) and does not seem to be present at older ages. Our findings may have policy implications regarding the choice of vaccine offered.
Discussion
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Cite This Study
Naveed et al. (2022) conducted a cohort in COVID-19 vaccination (n=3,095,414). mRNA-1273 vs. BNT162b2 was evaluated on Diagnosis of myocarditis during a hospitalization or emergency department visit within 21 days following the second dose (aOR 2.78, 95% CI 1.67-4.62). Receipt of a second dose of the mRNA-1273 COVID-19 vaccine was associated with significantly higher odds of myocarditis (aOR 2.78) compared to BNT162b2.