title: Effectiveness of the 23-valent polysaccharide vaccine against invasive pneumococcal disease in Navajo adults.
abstract: Invasive pneumococcal disease occurs 2-3-fold more often among Navajo adults than among adults in the general United States population. The objective of this observational study was to determine the effectiveness of the 23-valent pneumococcal polysaccharide vaccine (PPV23) among Navajo adults. Active surveillance identified cases of invasive pneumococcal disease during 1996-1997. Three control patients per case patient were matched according to underlying medical conditions, sex, age, and location of medical care. Effectiveness was calculated by regression analysis of case-control sets and by indirect cohort methodology. Diabetes and alcoholism occurred in 41% and 43% of 108 case patients, respectively; 62% of case patients and 64% of control patients were immunized. Overall vaccine effectiveness was 26% (95% confidence interval [CI], -29% to 58%); 15% (95% CI, -116% to 67%) for patients with diabetes and -5% (95% CI, -141% to 54%) for patients with alcoholism. Overall vaccine effectiveness, as determined by use of the indirect cohort methodology, was 35% (95% CI, -33% to 69%). PPV23 was not significantly effective among Navajo adults and may be inadequate to prevent serious pneumococcal disease in this population.
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA. andrea.benin@yale.edu
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Benin
authors.forename: Katherine L
authors.initials: KL
authors.lastname: O'Brien
authors.forename: James P
authors.initials: JP
authors.lastname: Watt
authors.forename: Raymond
authors.initials: R
authors.lastname: Reid
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Zell
authors.forename: Scott
authors.initials: S
authors.lastname: Katz
authors.forename: Connie
authors.initials: C
authors.lastname: Donaldson
authors.forename: Alan
authors.initials: A
authors.lastname: Parkinson
authors.forename: Anne
authors.initials: A
authors.lastname: Schuchat
authors.forename: Mathuram
authors.initials: M
authors.lastname: Santosham
authors.forename: Cynthia G
authors.initials: CG
authors.lastname: Whitney
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007198:Indians, North American; D008297:Male; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000208:ethnology* / Q000276:immunology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000276:immunology*; D012189:Retrospective Studies; D013296:Streptococcus pneumoniae / Q000276:immunology; D014481:United States
chemical_list: D022242:Pneumococcal Vaccines