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PLoS One. 2015 Mar 20;10(3):e0118283. doi: 10.1371/journal.pone.0118283. eCollection 2015.

A prospective study of the incidence of myocarditis/pericarditis and new onset cardiac symptoms following smallpox and influenza vaccination.

Author information

1
Military Vaccine Agency-Vaccine Healthcare Centers Network (currently Defense Health Agency, Immunization Healthcare Branch), Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America; Department of Medicine and Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
2
Department of Medicine and Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America; Allergy-Immunology-Immunizations, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America.
3
Military Vaccine Agency-Vaccine Healthcare Centers Network (currently Defense Health Agency, Immunization Healthcare Branch), Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America.
4
Cardiology Service, Department of Medicine, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America; Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States of America.
5
Department of Research Programs, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America.
6
Department of Pathology, Vassar Brothers Medical Center, Poughkeepsie, New York, United States of America.
7
Cardiology Service, Fort Belvoir Community Hospital, Fort Belvoir, Virginia, United States of America.
8
Integrated Cardiac Health Project, Walter Reed National Military Medical Center, Bethesda, Maryland, United States of America.
9
Allergy and Asthma Care Centers, Chantilly, Virginia, United States of America.
10
Military Vaccine Agency-Vaccine Healthcare Centers Network (currently Defense Health Agency, Immunization Healthcare Branch), Womack Army Medical Center, Fort Bragg, North Carolina, United States of America.
11
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America.
12
Cincinnati Children's Hospital Center for Global Health, Cincinnati, Ohio, United States of America.
13
Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
14
Department of Immunology, University of Washington, Seattle, Washington, United States of America.
15
Center for Biomedical Informatics, University of Tennessee Health Sciences Center, Memphis, Tennessee, United States of America; Oak Ridge National Laboratory, Oak Ridge, Tennessee, United States of America.

Abstract

BACKGROUND:

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.

PURPOSE:

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.

METHODS:

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.

CONCLUSIONS:

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.

PMID:
25793705
PMCID:
PMC4368609
DOI:
10.1371/journal.pone.0118283
[Indexed for MEDLINE]
Free PMC Article

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