Routine vaccination of young children with the 7-valent pneumococcal conjugate vaccine (PCV7) was launched in the United States in 2000. Although the incidence of invasive pneumococcal disease has since declined significantly, the effect of this measure on the hospitalization rate for pneumonia remains unknown.

The objective of the study by C.G. Grijalva et al. (USA), was to evaluate the effect of routine vaccination of children with the pneumococcal conjugate vaccine on the hospitalization rate for pneumonia of any etiology and pneumococcal pneumonia. In the study, data from Nationwide Inpatient Sample, the largest hospital patient base in the United States, was analyzed using the interrupted time series method. A comparison was made of the frequency of monthly hospitalization for the above pathology after the introduction of routine vaccination with the expected frequency calculated on the basis of data obtained before its introduction (1997-1999). The year the vaccine was introduced into clinical practice (2000) was excluded from the analysis.

According to the results, at the end of 2004, the rate of hospitalization for pneumonia of any etiology in children under 2 years of age who were the target group of the routine vaccination program decreased by 39% (confidence interval (CI) 95% 22-52). An annual decrease in the frequency of hospitalization for pneumonia of any etiology was also noted by 506 (291-675) episodes per 100,000 children under 2 years of age, which, in turn, prevented approximately 41,000 hospitalization episodes. for this pathology in 2004. An annual decrease in hospitalization for pneumonia in patients aged 18 to 39 years who have not been vaccinated was also noted.

During an 8-year study period, 10,659 (2%) children under the age of 2 were hospitalized for pneumococcal pneumonia. With the introduction of the planned vaccination program, a drop in the hospitalization rate for this disease was noted by 65% (47-77%), i.e. 17 hospitalization episodes avoided per 100,000 children in 2004.

Thus, the introduction of a routine vaccination program against the pneumococcal conjugate vaccine in childhood has led to a significant reduction in the frequency of hospitalization of children for pneumonia. According to the authors, the degree of reduction in this indicator reflects the proportion of pneumococcal pneumonia that can be prevented by vaccination.