For additional myopericarditis treatment guidelines, please see DoD Clinical Guidelines for Post-Smallpox Vaccine Associated Myopericarditis Algorithm (March 2013)


Myopericarditis is defined as a spectrum of disease caused by inflammation of the myocardium (muscle of the heart wall) and/or the pericardium, which is the sac-like covering surrounding the heart. There is evidence that suggests that some individuals may have this serious cardiac adverse event following smallpox vaccination.

People most at risk to develop this adverse event are young Caucasian males who are primary vaccinees.

Myopericarditis Case Definition includes:
  • Symptoms:
    • Chest pain, shortness of breath and palpitations
  • ECG abnormalities
  • Pericardial rub or effusion
  • Depressed left ventricular function
  • Elevated cardiac enzymes

Treatment recommendations for myopericarditis include seeking immediate medical care where an EKG and possibly an Echo can be obtained. Cardiac labs are also recommended.

Who do I contact for more assistance with myopericarditis cases?

The Worldwide DHA Immunization Healthcare Support Center should be contacted for consultation if a suspected case of myopericarditis is identified. In addition, the IHB Clinical Services maintains the DoD post-smallpox vaccine associated Myopericarditis Registry.

Is there any difference between the Dryvax Vaccine and ACAM2000 in regard to myopericarditis?

Pre-licensure surveillance with the newer ACAM vaccine revealed occurrence rates similar to Dryvax for myopericarditis.

Related References

Cassimatis D, Atwood JE, Engler R, Linz P, Grabenstein J, Vernalis M. (2004) Smallpox vaccination and myopericarditis. JACC;43(9):1503-10.

Eckart R. Love S. Atwood JE, Arness M, Cassimatis D. Campbell C. Boy S. et al. (2004) Incidence and follow-up of inflammatory cardiac complications after smallpox vaccination. JACC;44(1):201-5.

Helle, E.J., Koskenvuo, K., Pikkarainen, J. & Weckstrom, P. (1978). Myocardial complications of immunizations. Annuals of Clinical Research;10:280-287.

Karjalainen J, Heikkila J, Nieminen MS, Jalanko H, Kleemola M, Lapinleimu K, Sahi T. (1983). Etiology of mild acute infectious myocarditis: Relation to clinical features. Acta Medica Scandinavica;213:65-73.