Drastic changes in serotypes of carried pneumococci due to an increased vaccination rate in Hungary

Abstract

Introduction of the conjugate pneumococcal vaccine into the voluntary childhood vaccine program in Hungary in April 2009 resulted in a sharp increase of the vaccination rate. However, changes in serotypes as a consequence of vaccination should be considered. The aim of the authors was to compare pneumococci isolated from children with high-level and low-level vaccination rates. Nasal specimens from 854 children attending 20 nurseries at various locations in Hungary have been collected since 2009. The serotypes, antibiotic susceptibility and genetic relatedness of the isolated pneumococci were determined. 324 strains were isolated, and the carriage rate was 37.94%. The strains were sensitive to most antibiotics, except for macrolides. A definite suppression of vaccine types was detected during these 3 years, from the initial 78.85% to 35.30%. The authors conclude that the results reflect the efficacy of the vaccine, which underlines the need for the inclusion of pneumococcal vaccine into the list of obligatory vaccines.