title: Influenza vaccination of elderly persons. Reduction in pneumonia and influenza hospitalizations and deaths.
abstract: Effectiveness of influenza vaccination in reducing pneumonia and influenza hospitalizations and deaths among elderly members of a prepaid health plan was analyzed retrospectively. Two epidemics caused by the H3N2 subtype of type A influenza were studied. Vaccine derived from the H2N2 subtype of influenza A virus failed to protect against the Hong Kong (H3N2) virus during the 1968-1969 epidemic. Vaccine derived from the A/Hong Kong/68 (H3N2) virus yielded an estimated 72% (31% to 100%) reduction in hospitalization and 87% (52% to 100%) reduction in mortality during the 1972-1973 epidemic caused by A/England/72 (H3N2). These findings are consistent with those reported in vaccinated young persons, and hence it appears they may be broadly generalized.
mesh_terms: D000367:Age Factors; D000368:Aged; D006279:Health Maintenance Organizations; D006302:Health Services Research; D006760:Hospitalization / Q000639:trends; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000401:mortality / Q000517:prevention & control*; D009026:Mortality; D009922:Oregon; D011014:Pneumonia / Q000517:prevention & control*; D011024:Pneumonia, Viral / Q000517:prevention & control; D011336:Probability; D012189:Retrospective Studies; D014611:Vaccination / Q000706:statistics & numerical data
chemical_list: D007252:Influenza Vaccines