title: Nursing home outbreak of influenza A (H3N2): evaluation of vaccine efficacy and influenza case definitions.
abstract: OBJECTIVE
  Describe an outbreak of influenza A (H3N2); provide an analysis of vaccine efficacy; measure the sensitivity, specificity, and positive predictive value of 3 clinical case definitions of influenza.
  
  
  METHODS
  A nursing home in Washington County, Maryland. The outbreak involved 52 residents (attack rate = 47.7%) and at least 10 of 140 employees (minimum attack rate = 7.1%).
  
  
  RESULTS
  Twenty-five residents exhibited a 4-fold or greater increase in titer to influenza A/Sichuan/2/87. Vaccine efficacy was measured at -7.1%, suggesting that the influenza vaccine in 1988/1989 did not offer optimal protection against influenza A infection for the institutionalized elderly.
  
  
  CONCLUSIONS
  The outbreak was a clear indicator of the need for rapid diagnosis. With the use of rapid diagnostic tests, influenza A could have been detected in time to use amantadine.
authors.affiliation: Division of Outbreak Investigation, Maryland Department of Health and Mental Hygiene, Baltimore 21201.
authors.forename: J L
authors.initials: JL
authors.lastname: Taylor
authors.forename: D M
authors.initials: DM
authors.lastname: Dwyer
authors.forename: T
authors.initials: T
authors.lastname: Coffman
authors.forename: C
authors.initials: C
authors.lastname: Groves
authors.forename: J
authors.initials: J
authors.lastname: Patel
authors.forename: E
authors.initials: E
authors.lastname: Israel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000302:isolation & purification; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000276:immunology / Q000302:isolation & purification; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes; D009740:Nursing Staff; D012703:Serotyping
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines