title: Clinical effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia in middle-aged and older adults: a matched case-control study.
abstract: The 23-valent polysaccharide pneumococcal vaccine is currently recommended in elderly and high-risk adults. Its efficacy against invasive pneumococcal disease has been demonstrated, but its effectiveness in preventing pneumonia remains uncertain. This study assessed the clinical effectiveness of vaccination against pneumonia among middle-aged and older adults. We conducted a population-based case-control study including 304 case patients over 50 years old with radiographically confirmed pneumococcal pneumonia (94 bacteremic and 210 nonbacteremic cases) and 608 outpatient control subjects (matched by primary care centre, age, sex and risk stratum). Adjusted odds ratios (ORs) for vaccination were calculated using conditional logistic regression, controlling for underlying conditions. Vaccine effectiveness against all pneumococcal pneumonia was 48% (OR: 0.52; 95% confidence interval [CI]: 0.37-0.73). Vaccination was effective against bacteremic cases (OR: 0.34; 95% CI: 0.27-0.66) as well as nonbacteremic cases (OR: 0.58; 95% CI: 0.39-0.86). Vaccine effectiveness was highest against bacteremic infections caused by vaccine types (OR: 0.24; 95% CI: 0.09-0.66). These findings confirm the effectiveness of the vaccine against invasive disease, but they also support the benefit of vaccination in preventing nonbacteremic pneumococcal pneumonia.
authors.affiliation: Primary Care Service of Tarragona-Valls, EPIVAC Study Group, Institut Catalá de la Salut, Prat de la Riba 39, Tarragona 43001, Spain. avila.tarte.ics@gencat.cat
authors.forename: Angel
authors.initials: A
authors.lastname: Vila-Corcoles
authors.forename: Elisabet
authors.initials: E
authors.lastname: Salsench
authors.forename: Teresa
authors.initials: T
authors.lastname: Rodriguez-Blanco
authors.forename: Olga
authors.initials: O
authors.lastname: Ochoa-Gondar
authors.forename: Cinta
authors.initials: C
authors.lastname: de Diego
authors.forename: Amparo
authors.initials: A
authors.lastname: Valdivieso
authors.forename: Imma
authors.initials: I
authors.lastname: Hospital
authors.forename: Frederic
authors.initials: F
authors.lastname: Gomez-Bertomeu
authors.forename: Xavier
authors.initials: X
authors.lastname: Raga
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016470:Bacteremia / Q000517:prevention & control; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D022242:Pneumococcal Vaccines / Q000494:pharmacology*; D011018:Pneumonia, Pneumococcal / Q000276:immunology / Q000517:prevention & control*; D012307:Risk Factors; D013030:Spain; D016896:Treatment Outcome
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D022242:Pneumococcal Vaccines