RANDOMIZED TRIAL OF 23-VALENT PNEUMOCOCCAL CAPSULAR POLYSACCHARIDE VACCINE IN PREVENTION OF PNEUMONIA IN MIDDLE-AGED AND ELDERLY PEOPLE

Background We assessed the effectiveness of a 23-valent pneumococcal v accine in the prevention of pneumococcal pneumonia and of pneumonia ov erall in nonimmunocompromised middle-aged and elderly people. Methods The prospective, multicentre, double-blind, randomised, placebo-contro lled trial was carried out across departments of infectious diseases a t six tertiary-care or university hospitals in Sweden. 691 nonimmunoco mpromised patients aged 50-85 years who had been treated as inpatients for community-acquired pneumonia (CAP) were randomly assigned either 23-valent pneumococcal capsular polysaccharide vaccine or placebo (sod ium chloride). We used Cox regression models to estimate the relative risks of pneumonia overall and pneumococcal pneumonia for the placebo group compared with the vaccine group. Findings 63 (19%) of 339 patien ts in the vaccine group and 57 (16%) of 352 patients in the placebo gr oup developed a new pneumonia, corresponding to a relative risk over t ime for the placebo group compared with the vaccine group of 0.83 (95% CI 0.58-1.12, p=0.31). Pneumococcal pneumonia was diagnosed in 16 (4. 5%) patients in the placebo group and in 19 (5.6%) in the vaccine grou p, corresponding to a relative risk for the placebo group of 0.78 (95% CI 0.40-1.51, p=0.45). We found no difference in the death rate betwe en the two study groups. Interpretation The 23-valent pneumococcal pol ysaccharide vaccine did not prevent pneumonia overall or pneumococcal pneumonia in middle-aged and elderly individuals.