Objective: To examine the effectiveness of pneumococcal polysaccharide vaccine (PPV) among approximately 40,000 community-dwelling men aged 45 years and older in the California Men's Health Study (CMHS) cohort.
Methods: All participants completed an extensive questionnaire at baseline (2002-2003) and were followed for the occurrence of invasive pneumococcal disease (IPD) or all-cause pneumonia hospitalization through the end of 2009. Immunization status and incident IPD and pneumonia cases were ascertained through electronic medical records. The associations between vaccination and IPD or pneumonia hospitalization were assessed using time-dependent Cox proportional models to account for sociodemographics, time-updated vaccination status, and comorbidities.
Results: The median follow-up period of the 39,222 participants was 7.3 years. Among them, 11,902 (30.3%) had received at least one PPV vaccine at baseline and 7653 (19.5%) received their first PPV vaccine during the follow-up. There were 17 pneumococcal bacteremia cases, 647 hospitalized pneumonia cases, and no pneumococcal meningitis cases. The results suggested a reduced risk of pneumococcal bacteremia among men vaccinated at age ≥65 (adjusted hazard ratio [HR]: 0.35; 95% confidence interval [CI]: 0.06-1.91; p=0.22). PPV vaccination did not show a protective effect against all-cause pneumonia hospitalization (adjusted HR: 1.18; 95% CI: 1.02-1.37, p=0.03) among men vaccinated before 65 years old, but a moderate protective effect was suggested among men without chronic obstructive pulmonary diseases who were vaccinated after 65 years old (adjusted HR: 0.84; 95% CI: 0.67-1.06, p=0.15).
Conclusions: The findings in this large cohort of men in Southern California suggested a benefit of PPV for protection against pneumococcal bacteremia among men vaccinated at age 65 years and older. PPV might not provide adequate protection against all-cause pneumonia hospitalization among men.
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