The May issue of the renowned medical journal The New England Journal of Medicine published the results of a study recently completed by American scientists to evaluate the effectiveness of the pneumococcal polysaccharide vaccine for the prevention of pneumococcal pneumonia and bacteremia in the elderly.

Pneumococcus (Streptococcus pneumoniae) is known to be the main causative agent of pneumonia in elderly patients, however, it is not yet known whether immunization with pneumococcal polysaccharide vaccine reduces the risk of this disease.

A retrospective analysis of data from 47,365 patients aged 65 and over over a 3-year period was performed. During the analysis, according to medical documentation, the following events were recorded: cases of hospitalization of patients for pneumonia; cases of pneumonia not requiring hospital treatment and cases of pneumococcal bacteremia. The study examined the relationship between vaccination with pneumococcal polysaccharide vaccine and the risk of each of the recorded events, taking into account age, gender, stay in a nursing home, smoking, health status and influenza vaccination.

During the study period, 1428 cases of hospitalization for community-acquired pneumonia, 61 cases of pneumococcal bacteremia and 3061 patients were diagnosed with mild pneumonia, which did not require hospital treatment.

Immunization with the pneumococcal polysaccharide vaccine has been shown to significantly reduce the risk of pneumococcal bacteremia (relative risk (RR) = 0.56; 95% confidence interval (CI) from 0.33 to 0.93). At the same time, vaccination had virtually no effect on the hospitalization rate for pneumonia (RR = 1.14, 95% CI - 1.02 to 1.28), on the incidence of mild pneumonia (RR = 1.04, 95% CI - 0.96 to 1.13), and generally the incidence of community-acquired pneumonia (RR = 1.07, 95% CI - 0.99 at 1.14) in this category of patients.

According to the results of this study, the pneumococcal polysaccharide vaccine is effective in preventing bacteremia, but it does not prevent the development of pneumococcal pneumonia, which is the most common manifestation of pneumococcal infection. Therefore, there is a need to seek other approaches for the prevention of pneumococcal pneumonia in the elderly.