SARS-CoV-2 Vaccination and Myocarditis in a Nordic Cohort Study of 23 Million Residents

Ø. Karlstad, P. Hovi, Anders Husby, T. Härkänen, R. Selmer, N. Pihlström, J. V. Hansen, H. Nohynek et al.

JAMA cardiology, 2022

195 citations

Abstract

Key Points Question Is SARS-CoV-2 messenger RNA (mRNA) vaccination associated with risk of myocarditis? Findings In a cohort study of 23.1 million residents across 4 Nordic countries, risk of myocarditis after the first and second doses of SARS-CoV-2 mRNA vaccines was highest in young males aged 16 to 24 years after the second dose. For young males receiving 2 doses of the same vaccine, data were compatible with between 4 and 7 excess events in 28 days per 100 000 vaccinees after second-dose BNT162b2, and between 9 and 28 per 100 000 vaccinees after second-dose mRNA-1273. Meaning The risk of myocarditis in this large cohort study was highest in young males after the second SARS-CoV-2 vaccine dose, and this risk should be balanced against the benefits of protecting against severe COVID-19 disease.

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

• DOI
• PubMed
• Free full text
• Publisher page

Related studies

• Improving sleep quality leads to better mental health: A meta-analysis of randomised controlled trials Sleep Medicine Reviews, 2021
• Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study Lancet. Infectious Diseases (Print), 2021
• Occupation and risk of severe COVID-19: prospective cohort study of 120,075 UK Biobank participants Occupational and Environmental Medicine, 2020
• Clinical presentation and virological assessment of confirmed human monkeypox virus cases in Spain: a prospective observational cohort study The Lancet, 2022
• Comparison of the characteristics, morbidity, and mortality of COVID-19 and seasonal influenza: a nationwide, population-based retrospective cohort study The Lancet Respiratory Medicine, 2020
• Lifestyle risk factors, inflammatory mechanisms, and COVID-19 hospitalization: A community-based cohort study of 387,109 adults in UK Brain, behavior, and immunity, 2020

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free