Long-term effect of 10-valent pneumococcal conjugate vaccine on nasopharyngeal carriage of Streptococcus pneumoniae in children in Brazil

Abstract Brazil introduced the 10-valent pneumococcal vaccine (PCV10) to the routine national immunization program (NIP) in March 2010. In 2017, we investigated the effects of PCV10 on nasopharyngeal carriage of vaccine-types (VT) and non-vaccine-types (NVT) of Streptococcus pneumoniae (Spn) among children living in Sao Paulo city. We also compared the prevalence of VT and NVT with previous carriage surveys performed in 2010 (baseline) and 2013. Method The carriage survey was conducted among 531 children, aged 12 months to Results No statistical difference was found in the prevalence of Spn either by culture (59.7%) or by qPCR (61.2%). Spn carriage increased from 40.3% (baseline) to 59.7% (2017 survey) (p  Conclusion After 7 years of PCV10 introduction in the NIP, colonization by VT among toddlers decreased substantially to a residual level, along with substantial serotype replacement by novel serotypes not present in any current conjugated pneumococcal vaccine and serotype 19A. The present findings can assist policy decisions in Brazil.