Four-Year Study of COVID-19 Vaccines Brings New Insights, Valuable Data, Expanded Collaboration

This pan-Canadian initiative, led by the Canadian Cardiovascular Society (CCS), began during the global pandemic in 2022 amid reports of rare cases of myopericarditis after mRNA COVID-19 vaccination.

OTTAWA — A four-year national cardiovascular surveillance study on the long-term impact of mRNA COVID-19 vaccination, funded by the Public Health Agency of Canada, has produced valuable insights, a rich repository of data, and new directions for research.

The $6.7-million study, called MYCOVACC (Canadian Cardiovascular Society National Active Surveillance Study of MYocarditis and/or Pericarditis following mRNA COVID-19 VACCination), involved more than 600 patients and the top cardiology researchers at 34 adult and pediatric study sites across Canada. Myocarditis is inflammation of the heart muscle and pericarditis is inflammation of the lining surrounding the heart muscle.

“While funding now has ended, this initiative has been a huge success,” says cardiologist Dr. Nathaniel Hawkins of the University of British Columbia, who led the pan-Canadian effort, which ran from September 1, 2022 to March 31, 2026. “We have a wealth of data to analyze before publishing more of our findings. No doubt, this work will encourage future research directions.”

The only Canadian study of its kind, MYCOVACC delivered:

• an impactful peer-reviewed journal article in the Canadian Journal of Cardiology;
• five conference presentations;
• three continuing professional development webinars (mostly recently on March 11, 2026), and
• educational and clinical tools including two accredited self-assessment programs and a podcast on the CCS website.

Further publications are planned for 2026 and 2027. Clinical resources and information for patients and healthcare providers will continue to be made available on the CCS website here.

More than 500 patients with post-vaccine myopericarditis and 100 patients with post-COVID-19 myopericarditis participated in the study, representing one of the largest cohorts in the world. Enrolment is now closed.

Among early scientific findings:

• although rare, post-vaccine myopericarditis is most common in young men (less than age 30), usually occurring after the second dose;
• over 80% of patients had a mild presentation that resolved quickly with only 2% of patients being at high risk of significant cardiac complications; and,
• cardiac MRI is the best diagnostic tool for this condition.

What made MYCOVACC especially powerful was the cross-disciplinary participation of experts from a number of fields, including heart failure specialists, heart rhythm specialists, cardiovascular magnetic resonance imaging specialists, pediatric cardiologists, public health physicians, and primary care physicians.

“Thanks to the Public Health Agency of Canada for funding this study and to all those who participated in this important project, most especially members of the Steering Committee, Scientific and Data Management Committee, and Integrated Knowledge Translation Committee,” Dr. Hawkins says. The names of these individuals can be found under Governance here on the CCS website.

The MYCOVACC team’s findings support informed decision-making about vaccinations, particularly in children and young adults.

For more information, please contact:
Sarah Muldoon
Director of Communications
Canadian Cardiovascular Society
muldoon@ccs.ca  

About the Canadian Cardiovascular Society:
The CCS is the national voice for cardiovascular clinicians and scientists, representing more than 2,500 cardiologists, cardiac surgeons and other heart health specialists across Canada. We advance heart health for all by setting standards for excellence in heart health and care, building the knowledge and expertise of the heart team, and influencing policy and advocating for the heart health of all Canadians. For further information on the CCS visit: https://ccs.ca/en/

About the Public Health Agency of Canada:
The Public Health Agency of Canada is part of the federal health portfolio. Its activities focus on preventing and reducing chronic diseases and injuries, preparing for and responding to public health threats and emergencies, and promoting health, well-being and equality. Visit: https://www.canada.ca/en/public-health

Email: mycovacc@ccs.ca
Website: https://ccs.ca/mycovacc/