title: Adverse events associated with smallpox vaccination in the United States, January-October 2003.
abstract: BACKGROUND
  On January 24, 2003, the US Department of Health and Human Services (DHHS) implemented a preparedness program in which smallpox (vaccinia) vaccine was administered to federal, state, and local volunteers who might be first responders during a bioterrorism event.
  
  
  OBJECTIVE
  To describe results from the comprehensive DHHS smallpox vaccine safety monitoring and response system.
  
  
  METHODS
  Descriptive study of adverse event reports from the DHHS smallpox vaccine safety monitoring and response system received between January 24 and October 31, 2003, through the Vaccine Adverse Event Reporting System (VAERS) and the Centers for Disease Control and Prevention. A total of 37,901 volunteers in 55 jurisdictions received at least 1 dose of smallpox vaccine.
  
  
  METHODS
  Number of vaccinations administered and description of adverse events and reporting rates.
  
  
  RESULTS
  A total of 38,885 smallpox vaccinations were administered, with a take rate of 92%. VAERS received 822 reports of adverse events following smallpox vaccination (overall reporting rate, 217 per 10,000 vaccinees). A total of 590 adverse events (72%) were reported within 14 days of vaccination. Nonserious adverse events (n = 722) included multiple signs and symptoms of mild and self-limited local reactions. One hundred adverse events (12%) were designated as serious, resulting in 85 hospitalizations, 2 permanent disabilities, 10 life-threatening illnesses, and 3 deaths. Among the serious adverse events, 21 cases were classified as myocarditis and/or pericarditis and 10 as ischemic cardiac events that were not anticipated based on historical data. Two cases of generalized vaccinia and 1 case of postvaccinial encephalitis were detected. No preventable life-threatening adverse reactions, contact transmissions, or adverse reactions that required treatment with vaccinia immune globulin were identified. Serious adverse events were more common among older revaccinees than younger first-time vaccinees.
  
  
  CONCLUSIONS
  Rigorous smallpox vaccine safety screening, educational programs, and older vaccinees may have contributed to low rates of preventable life-threatening adverse reactions. Other rare, clinically significant, or unexpected cardiac adverse events were detected by timely review of VAERS data and intensive clinical case investigation.
authors.affiliation: Smallpox Vaccine Adverse Event Monitoring and Response Activity, Epidemiology and Surveillance Division, National Immunization Program, Centers for Disease Control and Prevention, Atlanta, Ga 30333, USA. ccasey@cdc.gov
authors.forename: Christine G
authors.initials: CG
authors.lastname: Casey
authors.forename: John K
authors.initials: JK
authors.lastname: Iskander
authors.forename: Martha H
authors.initials: MH
authors.lastname: Roper
authors.forename: Eric E
authors.initials: EE
authors.lastname: Mast
authors.forename: Xiao-Jun
authors.initials: XJ
authors.lastname: Wen
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Török
authors.forename: Louisa E
authors.initials: LE
authors.lastname: Chapman
authors.forename: David L
authors.initials: DL
authors.lastname: Swerdlow
authors.forename: Juliette
authors.initials: J
authors.lastname: Morgan
authors.forename: James D
authors.initials: JD
authors.lastname: Heffelfinger
authors.forename: Charles
authors.initials: C
authors.lastname: Vitek
authors.forename: Susan E
authors.initials: SE
authors.lastname: Reef
authors.forename: La Mar
authors.initials: LM
authors.lastname: Hasbrouck
authors.forename: Inger
authors.initials: I
authors.lastname: Damon
authors.forename: Linda
authors.initials: L
authors.lastname: Neff
authors.forename: Claudia
authors.initials: C
authors.lastname: Vellozzi
authors.forename: Mary
authors.initials: M
authors.lastname: McCauley
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Strikas
authors.forename: Gina
authors.initials: G
authors.lastname: Mootrey
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems; D006801:Humans; D011159:Population Surveillance; D012900:Smallpox Vaccine / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology
chemical_list: D012900:Smallpox Vaccine