Despite availability of conjugate (PCV) and pneumococcal polysaccharide vaccines (PPV23), pneumococcal disease remains a global health problem. Emergence of non-vaccine serotypes continues to be a threat. As part of an ongoing program, literature was reviewed to inform recent changes in serotype distribution.
Medline, EMBASE and Cochrane databases were searched from February 2017–May 2019. Serotype distribution data for children ≤5 years were extracted and summarized.
Serotype data were available in 51 articles covering varying periods from 2012 onwards, including 39 publications from areas/periods where pediatric PCV was part of immunization programs. Most (30) papers covered nasopharyngeal carriage, 21 covered invasive pneumococcal disease (IPD), one each covered acute otitis media and non-IPD, and three pooled IPD and non-IPD. Overall, PCV13, PPV23-specific and non-vaccine serotypes accounted for 39.7%, 27.8% and 32.4% of serotyped isolates, respectively. Six of the 10 most prevalent serotypes were PCV13-specific. Among PPV23 serotypes, 15B/C, 11A and 10A ranked in the top 10. Global prevalence of serotypes 22F and 33F was 0.7% and 0.8%, respectively. The most prevalent non-vaccine serotypes were 23B, 15A/F, 23A, 21 and 16F.
PCV serotypes remain responsible for a significant burden of pneumococcal disease in children, even in countries using PCV.