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

Abstract

© 2 0 0 8 L A N D E S B I O S C I E N C E . D O N O T D I S T R I B U T E .vaccination site. 3 Moderate to severe adverse reactions include bullous erythema multiforme (Stevens-Johnson syndrome), eczema vaccinatum, generalized vaccinia, progressive vaccinia, and postvaccinal encephalitis. 3 More recently, the Department of Defense resumed smallpox vaccination for US military forces amid growing concerns that smallpox might be employed as a bioterrorist weapon. 4 Following reinstatement, reported adverse events were generally mild in nature, with the exception of an increased risk of myopericarditis predominantly among white males aged 21-44 years of age. 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. 10 ResultsOf the 55,021 Millennium Cohort participants who completed both a baseline and follow-up questionnaire, 45,284 had concordant self-reported and electronic smallpox vaccination records. Individuals vaccinated before taking their baseline survey (n = 74), and individuals vaccinated during the 30 days period prior to starting or while taking their follow-up survey (n = 283) were excluded. In addition, individuals who deployed to the Global War on Terrorism (GWOT) before completing their baseline survey (n = 2,378), completed their follow-up survey during a deployment (n = 1,672), or who were missing demographic or military covariate data (n = 405) were excluded. After exclusion criteria were applied, 40,472 individuals remained for analysis, 8,793 of whom received the smallpox vaccine and 31,679 who did not.The population was stratified by deployment status to GWOT, and characteristics of vaccinated and unvaccinated individuals

Trajectories of trauma symptoms and resilience in deployed US military service members: Prospective cohort study

“…In evaluating the data, we note that although the initial response rate to invitation in the Millennium Cohort Study was 36%, multiple studies of possible reporting and selection biases in baseline cohort data suggest reliable reporting, minimal response bias and a representative sample of military personnel, including deployers. 2,3,7,38-44 Several participants had missing data; however, trajectory solutions with and without missing data did not differ. It is possible that the use of self-reported symptom data to identify individuals with chronic post-traumatic stress might be less precise than medical diagnosis; however, previous studies using questionnaire instruments for PTSD have shown good agreement with medical diagnosis.…”

Health impact of US military service in a large population-based military cohort: findings of the Millennium Cohort Study, 2001-2008

“…Beginning with the 2004-2006 survey, the questionnaire also asked whether members received the smallpox vaccine after 2001. These data have been used to assess differences between self-reported vaccination history and electronic records [11,13], as well as to identify any associated health differences for concordant or discordant groups [21]. …”

A Prospective Study of Depression Following Combat Deployment in Support of the Wars in Iraq and Afghanistan

“…However, multiple investigations of possible reporting and selection biases in baseline Millennium Cohort data suggest reliable reporting, minimal response bias, and a representative sample of military personnel, including deployers. 14,15,[30][31][32][33][34][35]37,73,81 Use of the PHQ along with the DSM-IV criteria has shown to correlate well with a physician's assessment of depression symptoms, 32 and the PHQ is internally valid in Millennium Cohort members. 32 However, the use of a standardized instrument for self-reported data as a surrogate for depression diagnosis is imperfect.…”