Key Facts

  • Study compares risks of myocarditis, pericarditis and cardiac arrhythmia following a first and second dose of ChAdOx1 (Oxford-AstraZeneca), BNT162b2 mRNA (Pfizer-BioNTech) and RNA-1273 (Moderna) vaccine, and following COVID-19 infection.
  • Study shows increased risk of myocarditis with the first dose of ChAdOx1 (Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) vaccines and the first and second doses of the mRNA-1273 (Moderna) vaccine.
  • However, the risk of myocarditis was much higher following COVID-19 infection.
  • Study also showed increased risks of pericarditis and cardiac arrhythmia following a positive COVID-19 test but not with any of the vaccines, apart from an increased risk of arrhythmia following a second dose of mRNA-1273 (Moderna). Subgroup analyses by age showed the increased risk of myocarditis associated with the two mRNA vaccines (BNT162b2 and mRNA-127) was present only in those younger than 40.
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