Myopericarditis following Smallpox Vaccination

Abstract

Myopericarditis has been a rare or unrecognized event after smallpox vaccinations with the New York City Board of Health strain of vaccinia virus (Dryvax; Wyeth Laboratories, Marietta, Pennsylvania). In this article, the authors report an attributable incidence of at least 140 clinical cases of myopericarditis per million primary smallpox vaccinations with this strain of vaccinia virus. Fifty-eight males and one female aged 21-43 years with confirmed or probable acute myopericarditis were detected following vaccination of 492,730 US Armed Forces personnel from December 15, 2002, through September 30, 2003. The cases were identified through sentinel reporting to military headquarters, active surveillance using the Defense Medical Surveillance System, or reports to the Vaccine Adverse Event Reporting System. The observed incidence (16.11/100,000) of myopericarditis over a 30-day observation window among 347,516 primary vaccinees was nearly 7.5-fold higher than the expected rate of 2.16/100,000 (95% confidence interval: 1.90, 2.34) among nonvaccinated, active-duty military personnel, while the incidence of 2.07/100,000 among 145,155 revaccinees was not statistically different from the expected background rate. The cases were predominantly male (58/59; 98.3%) and White (51/59; 86.4%), both statistically significant associations (p = 0.0147 and p = 0.05, respectively).

Dominance and Diversity in the Primary Human CD4 T Cell Response to Replication-Competent Vaccinia Virus

“…Defined epitopes may also be useful in comparing poxvirus vectors being studied as backbones to express heterologous Ags, in which a strong anti-insert response is desired and an immunodominating anti-vector response is disadvantageous. Myocarditis is a rare complication of vaccinia vaccination with infiltrating leukocytes and no virus in affected hearts (84,85), consistent with a possible autoimmune component. We detected allocross-reactivity (Fig.…”

Internet-Based Reporting to the Vaccine Adverse Event Reporting System: A More Timely and Complete Way for Providers to Support Vaccine Safety

“…For the smallpox vaccination program from 2002 to 2004, IBRs resulted in increased proportional usage of electronic reporting (50% vs 13.3% overall usage in VAERS), which in turn contributed to the timely detection of the unanticipated finding of myopericarditis in adults after smallpox vaccination. 20,21 When we excluded smallpox vaccination reports (16%) from the analysis, report completeness and timeliness remained higher for IBRs compared with NIBRs. Hence, IBRs proved to be effective in accomplishing a higher proportion of completeness and timeliness independent of smallpox vaccination publicity.…”

“…A shorter reporting interval provides a better chance for timely detection of serious or life-threatening events and, consequently, timely public health intervention. [16][17][18][19][20][21] Report completeness is critical to the validity of VAERS reports; for example, age and onset interval can provide important information on the biological plausibility of the reported AE being associated with the administered vaccine. [16][17][18][19] IBRs have the potential to reduce transcription and data-entry errors and result in more accurate data.…”

Self-reported adverse health events following smallpox vaccination in a large prospective study of US military service members

“…Reports have suggested an increased risk for myopericarditis. 5,7,8 Other short-term morbidities may be associated with the smallpox vaccine as well. 4,12 Although smallpox vaccinations are currently being monitored for short-term adverse events, 13,14 no surveillance system is in place to monitor potential long-term adverse outcomes.…”

“…Onset of myopericarditis symptoms in these cases occurred between 2 to 25 days following primary vaccination. [5][6][7][8][9] Most evaluations of vaccine safety rely on case series or retrospective reviews of acute health care. In contrast, the Millennium Cohort Study, the largest prospective study in military history designed to follow over 140,000 US service members for 21 years from 2001 through 2022, provides a unique opportunity to evaluate a wide range of subacute or chronic health outcomes potentially associated with smallpox vaccine.…”