A multiprovincial retrospective analysis of the incidence of myocarditis or pericarditis after mRNA vaccination compared to the incidence after SARS-CoV-2 infection
Zaeema Naveed,
Cherry Chu,
Mina Tadrous,
Areti-Angeliki Veroniki,
Julia Li,
Isabelle Rouleau,
Yossi Febriani,
Andrew Calzavara,
Sarah A. Buchan,
Sharifa Nasreen,
Kevin L. Schwartz,
James Wilton,
Chi Yon Seo,
Nisha Thampi,
Sarah E. Wilson,
Monika Naus,
Gaston De Serres,
Naveed Z. Janjua,
Jeffrey C. Kwong
Affiliations
Zaeema Naveed
British Columbia Centre for Disease Control, Vancouver, BC, Canada; School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
Cherry Chu
Women's College Hospital, Toronto, ON, Canada
Mina Tadrous
Women's College Hospital, Toronto, ON, Canada; ICES, Toronto, ON, Canada; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
Areti-Angeliki Veroniki
Knowledge Translation Program, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada; Institute for Health Policy, Management, and Evaluation, University of Toronto, Toronto, ON, Canada
Julia Li
British Columbia Centre for Disease Control, Vancouver, BC, Canada; School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada
Isabelle Rouleau
Institut National de Santé Publique Du Québec, Biological Risks Division, Montreal, QC, Canada
Yossi Febriani
Centre Hospitalier Universitaire (CHU) de Québec-Université Laval Research Center, Quebec City, QC, Canada
Andrew Calzavara
ICES, Toronto, ON, Canada
Sarah A. Buchan
ICES, Toronto, ON, Canada; Public Health Ontario, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada; Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, ON, Canada
Sharifa Nasreen
ICES, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
Kevin L. Schwartz
ICES, Toronto, ON, Canada; Public Health Ontario, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
James Wilton
British Columbia Centre for Disease Control, Vancouver, BC, Canada
Chi Yon Seo
Public Health Ontario, Toronto, ON, Canada
Nisha Thampi
Public Health Ontario, Toronto, ON, Canada; Children's Hospital of Eastern Ontario, Ottawa, ON, Canada
Sarah E. Wilson
ICES, Toronto, ON, Canada; Public Health Ontario, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada; Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, ON, Canada
Monika Naus
British Columbia Centre for Disease Control, Vancouver, BC, Canada
Gaston De Serres
Institut National de Santé Publique Du Québec, Biological Risks Division, Montreal, QC, Canada; Institut National de Sante Publique Du Québec, Biological and Occupational Risks Division, Quebec City, QC, Canada; Laval University, Department of Social and Preventive Medicine, Faculty of Medicine, Quebec City, QC, Canada
Naveed Z. Janjua
British Columbia Centre for Disease Control, Vancouver, BC, Canada; School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada; Centre for Health Outcomes and Evaluation, St Paul's Hospital, Vancouver, BC, Canada
Jeffrey C. Kwong
ICES, Toronto, ON, Canada; Public Health Ontario, Toronto, ON, Canada; Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada; Centre for Vaccine Preventable Diseases, University of Toronto, Toronto, ON, Canada; Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada; University Health Network, Toronto, ON, Canada; Corresponding author. ICES V1 06, 2075 Bayview Avenue Toronto, Ontario, Canada, M4N 3M5.
Objective: To compare myocarditis/pericarditis risk after COVID-19 mRNA vaccination versus SARS-CoV-2 infection, and to assess if myocarditis/pericarditis risk varies by vaccine dosing interval. Methods: In this retrospective cohort study, we used linked databases in Quebec, Ontario, and British Columbia between January 26, 2020, and September 9, 2021. We included individuals aged 12 or above who received an mRNA vaccine as the second dose or were SARS-CoV-2-positive by RT-PCR. The outcome was hospitalization/emergency department visit for myocarditis/pericarditis within 21 days of exposure. We calculated age- and sex-stratified incidence ratios (IRs) of myocarditis/pericarditis following mRNA vaccination versus SARS-CoV-2 infection. We also calculated myocarditis/pericarditis incidence by vaccine type, homologous/heterologous schedule, and dosing interval. We pooled province-specific estimates using meta-analysis. Results: Following 18,860,817 mRNA vaccinations and 860,335 SARS-CoV-2 infections, we observed 686 and 160 myocarditis/pericarditis cases, respectively. Myocarditis/pericarditis incidence was lower after vaccination than infection (IR [BNT162b2/SARS-CoV-2], 0.14; 95%CI, 0.07–0.29; IR [mRNA-1273/SARS-CoV-2], 0.28; 95%CI, 0.20–0.39). Within the vaccinated cohort, myocarditis/pericarditis incidence was lower with longer dosing intervals; IR (56 or more days/15–30 days) was 0.28 (95%CI, 0.19–0.41) for BNT162b2 and 0.26 (95%CI, 0.18–0.38) for mRNA-1273. Conclusion: Myocarditis/pericarditis risk was lower after mRNA vaccination than SARS-CoV-2 infection, and with longer intervals between primary vaccine doses.
