Skip to main content
King County logo
May 21, 2021

Select a tab below to navigate through sections:

  • Be aware of reports locally and nationally of myocarditis and pericarditis among persons who had received a COVID-19 vaccination in the two weeks prior.
  • Consider a diagnosis of myocarditis or pericarditis in any evaluation of chest pain following COVID-19 vaccination.
  • Inquire about recent COVID-19 vaccination in any patient presenting with symptoms consistent with myocarditis or pericarditis (chest pain or pressure, or shortness of breath, EKG abnormalities).
  • Report such cases promptly to the U.S. Vaccine Adverse Events Reporting System (VAERS:
    • It is recommended that the evaluating (not administering) provider report the incident to VAERS so that appropriate clinical details can be reported accurately and promptly.
  • Report cases of myocarditis or pericarditis within 2 weeks of any COVID-19 vaccination to Public Health – Seattle & King County by calling 206-296-4774 or faxing 206-296-4803, including information on vaccine manufacturer, vaccination date, dose number as well as history of prior SARS-CoV-2 infection.

Public Health is investigating 12 reported cases of myocarditis or pericarditis since early May among King County residents following the first or second dose of COVID-19 vaccine with either Pfizer or Moderna vaccines. Cases range in age from 16-66 years, (11 cases under 40 years) and the majority of cases are among males. At least three patients have been hospitalized, but no ICU admissions or deaths have been identified. The investigation is ongoing, and all data is preliminary.

The CDC is monitoring myocarditis/pericarditis in multiple safety systems, including the Vaccine Adverse Event Reporting System (VAERS) and the Vaccine Safety Datalink (VSD). To date, there has not been a safety signal identified in either VAERS or VSD. CDC is continuing to evaluate reports of myocarditis/pericarditis occurring after COVID-19 vaccination and will share more information as it becomes available.

A recent CDC Vaccine Safety Technical Subgroup report concluded that there are relatively few reports of myocarditis to date and that these cases seem to occur: predominantly in adolescents and young adults, more often in males than females, more often following dose 2 than dose 1, and typically within 4 days after vaccination. Most cases appear to be mild, and follow-up of cases is ongoing. At this time it is not clear if there is a causal association with vaccination. CDC continues to recommend COVID-19 vaccination for people 12 years and older.

To support ongoing monitoring for this potential adverse event, healthcare providers should evaluate patients with chest pain for myocarditis or pericarditis and inquire about recent COVID-19 vaccination; any such cases should be reported promptly to VAERS. Clinical features of myocarditis and pericarditis include chest pain or pressure, shortness of breath, electrocardiogram (EKG) changes and elevated cardiac biomarkers. Providers should elicit a detailed history including vaccination status and potential exposures to COVID-19. Patients should be tested for COVID-19 infection using a molecular (PCR) test.