Incremental effectiveness of pneumococcal vaccine on simultaneously administered influenza vaccine in preventing pneumonia and pneumococcal pneumonia among persons aged 65 years or older.

The effectiveness of simultaneously administered influenza and pneumococcal vaccines vs. influenza vaccine alone in preventing pneumonia, pneumococcal pneumonia and pneumococcal bacteraemia among the elderly was studied. The vaccines were offered to all persons aged 65 years or older (N=43,500) living in 35 administrative districts in Northern Finland. A total of 26,925 persons (62%) decided to participate. Allocation to the vaccination groups took place by year of birth (odd/even). The total follow-up of those vaccinated consisted of 38,037 person years. The incremental effectiveness of the pneumococcal vaccine was -20 (95% CI -50- + 10%) for pneumonia, -20 (95% CI -90- + 20%) for pneumococcal pneumonia and + 60% (95% CI -40- +90%) for pneumococcal bacteraemia. Thus the pneumococcal polysaccharide vaccine did not offer any additional protection from pneumonia among elderly people in Finland although it reduced the incidence of bacteraemia.