title: Postexposure effectiveness of varicella vaccine.
abstract: OBJECTIVE
  1) To describe the postexposure effectiveness of varicella vaccine in a homeless shelter; and 2) to demonstrate an effective public health intervention and its implications.
  
  
  METHODS
  A prospective observational study.
  
  
  METHODS
  A women and children's shelter in Philadelphia with 2 cases of varicella before intervention.
  
  
  METHODS
  Varicella in vaccinated and unvaccinated shelter residents; vaccine effectiveness for prevention of varicella when administered after exposure among children <13 years of age.
  
  
  RESULTS
  Sixty-seven shelter residents received varicella vaccine after exposure, including 42 children <13 years of age. One child who was unvaccinated developed varicella, but no vaccinated child developed typical disease. Vaccine effectiveness was 95.2% (95% CI, 81.6%-98.8%) for prevention of any disease and 100% for prevention of moderate or severe disease among the children <13 years of age.
  
  
  CONCLUSIONS
  When used within 36 hours after exposure to varicella in a setting where close contact occurred, varicella vaccine was highly effective in preventing further disease. This study provides support for the recent recommendation by the Advisory Committee on Immunization Practices to administer varicella vaccine after exposure: this practice should minimize the number of moderate or severe cases of disease and prevent prolonged outbreaks.
authors.affiliation: Department of Public Health Philadelphia, Philadelphia, Pennsylvania 19146, USA. barbara.watson@phila.gov
authors.forename: B
authors.initials: B
authors.lastname: Watson
authors.forename: J
authors.initials: J
authors.lastname: Seward
authors.forename: A
authors.initials: A
authors.lastname: Yang
authors.forename: P
authors.initials: P
authors.lastname: Witte
authors.forename: J
authors.initials: J
authors.lastname: Lutz
authors.forename: C
authors.initials: C
authors.lastname: Chan
authors.forename: S
authors.initials: S
authors.lastname: Orlin
authors.forename: R
authors.initials: R
authors.lastname: Levenson
mesh_terms: D002644:Chickenpox / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D019433:Chickenpox Vaccine / Q000008:administration & dosage; D002648:Child; D005260:Female; D006703:Ill-Housed Persons; D006798:Housing; D006801:Humans; D007223:Infant; D008297:Male; D015143:Philadelphia / Q000453:epidemiology; D011446:Prospective Studies; D013997:Time Factors; D014611:Vaccination
chemical_list: D019433:Chickenpox Vaccine