Serotype distribution of Streptococcus pneumoniae isolated from children in Moscow before
 and after introduction of 13-valent pneumococcal conjugate vaccination

Abstract

Introduction. In 2014, a 13-valent conjugated pneumococcal vaccine (PCV13) was introduced into the children’s immunization program in Russia. In this regard, to describe and analyze the epidemiology of pneumococcal infections, it is important to study and evaluate the distribution of serotypes and the effect of PCV13 vaccination on the serotype distribution of the nasopharyngeal Streptococcus pneumoniae isolates isolated in children from 2010 to 2018. Materials and methods. The study included 708 nasopharyngeal pediatric pneumococcal isolates recovered from 2010 to 2018, in patients under 5 years of age, who received inpatient and outpatient care at the National Medical Research Center for Children’s Health (Moscow). Serotyping was performed using antisera and / or molecular typing by PCR Results. In total, 33 different serotypes were identified in the S. pneumoniae collection. Six predominant serotypes were accounted for 68.6% of the total distribution and included serotypes: 19F, 6B, 23F, 14, 15B/C, 6A. The average prevalence of vaccine serotypes was of 77.7% in 2010-2015, with a significant decrease to 52% in 2018, which was accompanied by an increase in the prevalence of serotype 15B/C (16% in 2018) and serotypes 11A and 23A, from 1.1% in 2010 to 9.3% and 8% respectively in 2018. Conclusion. The use of PCV13 vaccination in Russia has led to a significant decrease in the carriage of pneumococcal vaccine serotypes. These results emphasize the need for careful monitoring of an ever-changing pneumococcal population.