Surveillance and follow up outcomes of myocarditis after mRNA COVID-19 vaccination in Australia.

Abstract

Clinical progression and medium-long term morbidity from myocarditis following mRNA COVID-19 vaccinations remains an important but undefined public health concern. We conducted prospective follow-up of individuals with either confirmed or probable myocarditis following monovalent Pfizer-BioNTech BNT162b2 or Moderna mRNA-1273 vaccination between 21 April 2021 and 5 July 2022 in Australia. Of 256 individuals who consented to follow up, mostly males following a second dose, 60% (133/221) had ongoing symptoms at 3-6 months and 35% (81/231) at 12-18 months. Self-reported ongoing exercise restrictions, medication requirements, and hospital re-presentations were associated with ongoing symptoms, as was a lower self-reported health status and quality of life. Clinical severity remained mild, with low hospitalisation rates and no deaths in the follow-up period and health-related quality of life improved over time. These findings support ongoing use of mRNA COVID-19 vaccines in at-risk individuals to prevent disease caused by SARS-CoV-2 infection.