A prospective study of the incidence of myocarditis/pericarditis and new onset cardiac symptoms following smallpox and influenza vaccination
- Uniformed Services Univ. of the Health Sciences, Bethesda, MD (United States)
- Uniformed Services Univ. of the Health Sciences, Bethesda, MD (United States); Walter Reed National Military Medical Center, Bethesda, MD (United States)
- Walter Reed National Military Medical Center, Bethesda, MD (United States)
- Vassar Brothers Medical Center, Poughkeepsie, NY (United States)
- Fort Belvoir Community Hospital, Fort Belvoir, VA (United States)
- Allergy and Asthma Care Centers, Chantilly, VA (United States)
- Womack Army Medical Center, Fort Bragg, NC (United States)
- Mayo Clinic, Rochester, MN (United States)
- Cincinnati Children's Hospital Center for Global Health, Cincinnati, OH (United States)
- Fred Hutchinson Cancer Research Center, Seattle, WA (United States)
- Bill and Melinda Gates Foundation, Seattle, WA (United States); Univ. of Washington, Seattle, WA (United States)
- Univ. of Tennessee Health Sciences Center, Memphis, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Univ. of British Columbia, Vancouver, BC (Canada)
Although myocarditis/pericarditis (MP) has been identified as an adverse event following smallpox vaccine (SPX), the prospective incidence of this reaction and new onset cardiac symptoms, including possible subclinical injury, has not been prospectively defined. The study's primary objective was to determine the prospective incidence of new onset cardiac symptoms, clinical and possible subclinical MP in temporal association with immunization. New onset cardiac symptoms, clinical MP and cardiac specific troponin T (cTnT) elevations following SPX (above individual baseline values) were measured in a multi-center prospective, active surveillance cohort study of healthy subjects receiving either smallpox vaccine or trivalent influenza vaccine (TIV). Results New onset chest pain, dyspnea, and/or palpitations occurred in 10.6% of SPX-vaccinees and 2.6% of TIV-vaccinees within 30 days of immunization (relative risk (RR) 4.0, 95% CI: 1.7-9.3). Among the 1081 SPX-vaccinees with complete follow-up, 4 Caucasian males were diagnosed with probable myocarditis and 1 female with suspected pericarditis. This indicates a post-SPX incidence rate more than 200-times higher than the pre-SPX background population surveillance rate of myocarditis/pericarditis (RR 214, 95% CI 65-558). Additionally, 31 SPX-vaccinees without specific cardiac symptoms were found to have over 2-fold increases in cTnT (>99th percentile) from baseline (pre-SPX) during the window of risk for clinical myocarditis/pericarditis and meeting a proposed case definition for possible subclinical myocarditis. This rate is 60-times higher than the incidence rate of overt clinical cases. No clinical or possible subclinical myocarditis cases were identified in the TIV-vaccinated group. In conclusion, passive surveillance significantly underestimates the true incidence of myocarditis/pericarditis after smallpox immunization. Evidence of subclinical transient cardiac muscle injury post-vaccinia immunization is a finding that requires further study to include long-term outcomes surveillance. Active safety surveillance is needed to identify adverse events that are not well understood or previously recognized.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1333076
- Journal Information:
- PLoS ONE, Vol. 10, Issue 3; ISSN 1932-6203
- Publisher:
- Public Library of ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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