title: Two outbreaks of influenza A (H3N2) in a Japanese nursing home in the winter of 1996-1997, with differing vaccine efficacy.
abstract: Sixty of 128 (46.9%) residents of a nursing home were immunized with two doses of the trivalent split influenza vaccine. They developed 7.4-11.5-fold antibody increases, with a 69-82% protection rate, presenting good immune response rates to the influenza vaccine. Two outbreaks of influenza A (H3N2) occurred. There were no significant antigenic differences among the vaccine strain and the strains isolated from both outbreaks in haemagglutination-inhibition tests, suggesting that the second might have been a reoccurrence. There were no residents who were infected in both outbreaks. The vaccine efficacy against clinical illness in the first outbreak of typical influenza-like-illness (ILI) was 51% (relative risk: 0.49), and the febrile period was reduced significantly by vaccination. In the second outbreak, however, in which all patients had atypical ILI with a high fever but not respiratory symptoms, vaccine efficacy was not apparent for unknown reason.
authors.affiliation: Department of Public Health, Niigata University School of Medicine, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Murayama
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: K
authors.initials: K
authors.lastname: Nerome
authors.forename: K
authors.initials: K
authors.lastname: Mizuta
authors.forename: K
authors.initials: K
authors.lastname: Kameyama
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D005334:Fever / Q000453:epidemiology; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000276:immunology / Q000302:isolation & purification; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D007564:Japan / Q000453:epidemiology; D008297:Male; D011446:Prospective Studies
chemical_list: D007252:Influenza Vaccines