MEDICAL ADVISORY: Evaluation, Management and Reporting of Myocarditis and Pericarditis Following mRNA COVID-19 Vaccination

Issued by:  Emily Groot, MPH, MD, FRCPC, Associate Medical Officer of Health

The risk of myocarditis or pericarditis following COVID-19 mRNA vaccination remains rare. Myocarditis or pericarditis following COVID-19 mRNA vaccination is relatively mild and resolves quickly in most individuals. The National Advisory Committee on Immunization (NACI) advises that the known risks of COVID-19 illness (including complications like myocarditis/pericarditis) outweigh the potential harms of having an adverse event following mRNA vaccination.

To support post-marketing vaccine safety surveillance, health care providers should identify and investigate all suspected cases of myocarditis/pericarditis. Health care providers are required to report suspected and confirmed cases of myocarditis or pericarditis temporally associated with vaccination, as well as other adverse events following immunization, to Public Health in a detailed and timely manner.

Evaluation and management of myocarditis/pericarditis

Health care providers are advised to follow Public Health Ontario’s (PHO) clinical practice guidance recommendations in the evaluation of symptoms consistent with myocarditis and pericarditis after COVID-19 mRNA vaccines:

• If an individual develops chest pain, shortness of breath, or palpitations following receipt of an mRNA vaccine, advise them to seek immediate medical attention
• All suspected cases of post-vaccine myocarditis/pericarditis should be evaluated by a physician, including consultation with a cardiologist as indicated
• In addition to a physical exam, initial investigations may include an electrocardiogram (ECG), troponins, and an echocardiogram
• Consider other potential causes of myocarditis/pericarditis, such as acute or prior SARS CoV-2 infection or other viral etiologies (e.g., enterovirus PCR and comprehensive respiratory viral pathogen testing)
• Additional investigations for suspected myocarditis or pericarditis following COVID-19 mRNA vaccine may be guided by the Brighton Collaboration case definitions. The Brighton myocarditis and pericarditis case definitions are categorized by level of diagnostic certainty, with level 1 being the most specific 
  • Level 1 of certainty (definitive case) for myocarditis is defined by elevated myocardial biomarkers (troponins) and at least one of
    • Abnormal imaging study (either abnormal cardiac magnetic resonance (cMR); or
    • Abnormal echocardiogram
  • Level 1 certainty for pericarditis is defined by at least two out of three of
    • Evidence of abnormal fluid collection or pericardial inflammation by imaging study (echocardiogram, cMR or computed tomographic (CT))
    • Physical exam finding(s) of pericardial friction rub and/or pulsus paradoxus on examination
    • Abnormal EKG findings (new and/or normalizes on recovery)

Reporting Adverse Events Following Immunization (AEFI)

• Fax the completed report of adverse event form to the Vaccine Preventable Disease Program at 905-688-8225
• If you are unsure whether or not to report an AEFI, report the event
• When completing the AEFI form, provide as much detail as possible on medical history, assessment, testing and treatment
• Ensure applicable documentation is provided to align with what is checked off in Sections 3 and 4 of the AEFI form

Re-vaccination with COVID-19 vaccines following myocarditis/pericarditis

NACI recommends:

• Those who experienced myocarditis (with or without pericarditis) after a dose of mRNA COVID-19 vaccine should wait to get another dose until more information is available
  • Some individuals may choose to receive another dose of vaccine after discussing risks and benefits with their health care provider
• Those who experienced pericarditis and either had no workup or had normal investigations can receive the next dose once they are symptom free and at least 90 days has passed since their last vaccination

More information

• Clinical guidance of the evaluation and management of events of myocarditis/pericarditis following mRNA vaccines in children and adults in Ontario
  • Hospital for Sick Children’s Myocarditis and pericarditis after mRNA COVID-19 vaccination in children: Interim guidance
  • Canadian Paediatric Society’s Clinical guidance for youth with myocarditis and pericarditis following mRNA COVID-19 vaccination
  • Canadian Journal of Cardiology article Myocarditis and pericarditis after COVID-19 mRNA vaccination: Practical considerations for care providers
• For questions related to AEFI reporting:
  • PHO- AEFI Reporting for Health Care Providers in Ontario: Fact Sheet
  • Ministry of Health - Appendix B: Provincial Case Definitions for Diseases of Public Health Significance
  • PHO – Vaccine Safety
    • Includes the technical brief Adverse Events of Special Interest (AESIs) for COVID-19 Vaccines Surveillance
  • Call the VPD program at 905-688-8248 or 1-888-505-6074 ext. 7396
  • Refer to the Memo: Updates to Adverse Events Following Immunization Reporting and Case Definitions
• For questions related to COVID-19 vaccination, call the COVID-19 Primary Care Info-Line at 905-688-8248 (press 7, then 1 for physicians)
• Patient Resource: Myocarditis/pericarditis and COVID-19 vaccines- fact sheet