Serotypes associated with invasive pneumococcal disease high-risk groups: a systematic review

This systematic review aimed to establish if higher-valent conjugate vaccines will provide significantly higher coverage and protection in high-risk groups than the 13-valent pneumococcal conjugate vaccine (PCV13). The PubMed, Science Direct, and Google Scholar search engines were searched for original articles that reported on the type of study, period of the study, high-risk group(s) involved, specimens collected, number of isolates, frequency of serotyped isolates, and serotypes/serogroups of isolates for inclusion. Data from 14 studies based in seven countries, and 789 serotyped/serogrouped isolates, were extracted. There was no significant difference (P = .23) between the frequency of the non-vaccine serotypes (51.6%) and the vaccine serotypes (48.4%). The 23-valent pneumococcal polysaccharide vaccine (PPV23) had the highest serotype coverage (36.5% ± 5.3%) identified among the high-risk groups. The serotype coverage of the vaccines was highest for the cancer group (26.2% to 40.5%) and lowest for the sickle cell disease group (20% to 28.9%). Higher-valent pneumococcal vaccines may provide significantly higher coverage for groups at a high risk of invasive pneumococcal diseases. There is a need to monitor the serotypes associated with high-risk groups.