Changes in serotype prevalence of Streptococcus pneumoniae in Southampton, UK between 2006 and 2018

Abstract

Streptococcus pneumoniae continues to cause significant disease burden. Whilst pneumococcal conjugate vaccines (PCV) have substantially reduced this burden, serotype replacement partially negates this success due to increased disease associated with non-vaccine serotypes (NVTs). Continued surveillance is therefore essential to provide crucial epidemiological data. Annual cross-sectional surveillance of paediatric pneumococcal carriage was started in Southampton, UK following PCV7 roll-out in 2006. Nasopharyngeal swabs were collected from children < 5 years old each winter (October to March) from 2006/07 and for each consecutive year until 2017/18. Pneumococcal serotype was inferred from whole genome sequencing data. A total of 1429 (32.5%) pneumococci were isolated from 4093 children. Carriage ranged from 27.8% (95%CI 23.7–32.7) in 2008/09 to 37.9% (95%CI 32.8–43.2) in 2014/15. Analyses showed that carriage increased in children aged 24–35 months (p < 0.001) and 47–60 months (p < 0.05). Carriage of PCV serotypes decreased markedly following PCV7 and/or PCV13 introduction, apart from serotype 3 where the relative frequency was slightly lower post-PCV13 (pre-PCV13 n = 7, 1.67%; post-PCV13 n = 13, 1.27%). Prevalence of NVTs implicated in increased disease was low with 24F (n = 19, 1.4%) being the most common followed by 9N (n = 11, 0.8%), 8 (n = 7, 0.5%) and 12F (n = 3, 0.2%).

Comparative genomic epidemiology of serotype 3 IPD and carriage isolates from Southampton, UK between 2005 and 2017

“…1c ). This contrasts with other PCV7 and PCV13 serotypes that have decreased over the same period [ 40 ]. For IPD the proportion of serotype 3 ranged from 0 % (all periods between 2008/09 and 2011/12) to a maximum of 16.7 % (average: 6.6 %) ( Fig.…”

“…On average the proportion of serotype 3 observed in carriage has remained relatively steady at 1.4 %, ranging from 0 to 3.9 %, which was observed in the 2011/12 winter period (). This contrasts with other PCV7 and PCV13 serotypes that have decreased over the same period [40]. For IPD the proportion of serotype 3 ranged from 0 % (all periods between 2008/09 and 2011/12) to a maximum of 16.7 % (average: 6.6 %) ().…”

Phase 3 Safety and Immunogenicity Study of a Three-dose Series of Twenty-valent Pneumococcal Conjugate Vaccine in Healthy Infants and Toddlers

“…and UK IPD surveillance data further demonstrated that PCV13 achieved near elimination of matched PCV7 serotypes over its decade of use. 40,41 Notably, a 3-dose series was recommended in Israel and UK at PCV13 introduction. 42,43 Assessment of various immune responses for PCVs is important because the mechanism of protection of PCVs against pneumococcal disease is multifactorial, and no minimum circulating IgG level predicting protection is established.…”

A narrative review of genomic characteristics, serotype, immunogenicity, and vaccine development of Streptococcus pneumoniae capsular polysaccharide

“…The introduction of pneumococcal conjugate vaccine (PCV), PCV13 in 2010 had a significant impact on serotype prevalence. The study found that proportion of PCV13 serotypes decreased, while non-PCV13 serotypes increased over time [ 9 ]. Recent study in Urumqi, China analyzed the serotype distribution and drug resistance of S. pneumoniae in children aged 8 years and under between 2010 and 2021.…”