Pneumococcal pneumonia in adults 60 years or older: Incidence, mortality and prevention.

Background: This study investigated the burden (incidence, mortality and serotype distribution) of pneumococcal pneumonia among older adults in the region of Tarragona (Spain).

Methods: Population-based cohort study involving 27,204 individuals ≥60 years in Tarragonès county (Southern Catalonia), who were prospectively followed between 01/12/2008 and 30/11/2011. Bacteremic and nonbacteremic (positive sputum culture and/or urinary antigen test) pneumococcal pneumonias were recruited.

Results: A total of 125 pneumococcal pneumonias (16 bacteremic and 109 nonbacteremic) was observed. Incidence rates (per 1000 person-years) were 0.21 (95% confidence interval [CI]: 0.13-0.35) for bacteremic cases and 1.45 (95% CI: 1.20-1.75) for nonbacteremic cases. Case-fatality rate was 10.4% (12.5% in bacteremic and 10.1% in nonbacteremic cases). Five serotypes (types 3, 6C, 19A, 22F and 35B) were the most common serotypes, accounting for 64.3% of overall isolated serotypes. 73.1% of cases were due to the strains included in the 23-valent vaccine whereas 53.6% were due to the strains included in the 13-valent vaccine.

Conclusion: The burden of pneumococcal pneumonia remains considerable (especially among oldest people and nursing-home residents) despite a publicly funded anti-pneumococcal vaccination program operative for several years.