title: Influenza vaccine effectiveness in preventing hospitalizations and deaths in persons 65 years or older in Minnesota, New York, and Oregon: data from 3 health plans.
abstract: This study developed methods and determined the impact of influenza vaccination on elderly persons in 3 large health plans: Kaiser Permanente Northwest, HealthPartners, and Oxford Health Plans. Data for the 1996-1997 and 1997-1998 seasons were extracted from administrative databases. Subjects were health plan members > or = 65 years old. Comorbid conditions collected from the preceding year were used for risk adjustment with logistic regression. The virus-vaccine match was excellent for year 1 and fair for year 2. Both years, during peak and total periods, vaccination reduced all causes of death and hospitalization for pneumonia and influenza: hospitalizations were reduced by 19%-20% and 18%-24% for years 1 and 2, respectively, and deaths were reduced by 60%-61% and 35%-39% for the same periods. These results show that all elderly persons should be immunized annually for influenza. The methods used in this study are an efficient cost-effective way to study vaccine impact and similar questions.
authors.affiliation: HealthPartners Research Foundation, Minneapolis, MN 55440-1524, USA.
authors.forename: J
authors.initials: J
authors.lastname: Nordin
authors.forename: J
authors.initials: J
authors.lastname: Mullooly
authors.forename: S
authors.initials: S
authors.lastname: Poblete
authors.forename: R
authors.initials: R
authors.lastname: Strikas
authors.forename: R
authors.initials: R
authors.lastname: Petrucci
authors.forename: F
authors.initials: F
authors.lastname: Wei
authors.forename: B
authors.initials: B
authors.lastname: Rush
authors.forename: B
authors.initials: B
authors.lastname: Safirstein
authors.forename: D
authors.initials: D
authors.lastname: Wheeler
authors.forename: K L
authors.initials: KL
authors.lastname: Nichol
mesh_terms: D000367:Age Factors; D000368:Aged; D006279:Health Maintenance Organizations / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology* / Q000401:mortality / Q000517:prevention & control*; D007297:Inpatients / Q000706:statistics & numerical data; D008910:Minnesota; D009518:New York; D009922:Oregon; D010045:Outpatients / Q000706:statistics & numerical data; D012044:Regression Analysis; D018570:Risk Assessment; D012307:Risk Factors; D012621:Seasons; D013997:Time Factors
chemical_list: D007252:Influenza Vaccines