Speakers - 2026

Title: Impact of pneumococcal conjugate vaccine on antibiotic resistant serotypes in invasive pneumococcal diseases among hospitalised children aged less than 5 years in rural gambia

Abstract

Introduction: The pneumococcal conjugate vaccines (PCVs) have significantly reduced vaccine-type (VT) invasive pneumococcal diseases (IPD) in The Gambia. This study assessed the impact of PCVs on antibiotic-resistant serotypes in IPD among hospitalized children.

Method: We conducted surveillance of IPD in hospitalized young children between 2008 and 2023 in rural Gambia. Streptococcus pneumoniae was identified by morphology and optochin sensitivity and serotyped using latex agglutination and Quellung methods. Antibiotic sensitivity was determined using the Kirby-Bauer disc diffusion method and isolates resistant to ≥1 antibiotic class were classified as resistant. We performed descriptive statistics to assess resistance rates and serotype patterns across four time periods.

Results: Out of 321 invasive isolates from hospitalized children analyzed, a significant proportion (74%, n=263) were obtained from blood cultures. Most patients were < 2 years old (66%, n=211). The incidence of VT IPD hospitalisations significantly decreased, while non-vaccine type (NVT) pneumococci, especially serotype 12F, increased. Between 2008 and 2016, the proportion of antibiotic resistance among the most prevalent VT serotypes declined (1(14% to 6%), 5(23% to 5%), 6A (14% to 1%) and 14(16% to 6%), with a reduction in overall case incidence. In contrast, the proportion of resistance serotype 12F increased from 6% to 12% and resistance by serotypes among the individual antibiotics remained relatively stable.

Conclusion: PCVs have substantially reduced the prevalence of antibiotic-resistant vaccine-type pneumococci. Serotype 12F has emerged as a leading cause of IPD hospitalisation; therefore, adoption of higher valent PCVs containing 12F is needed to reduce IPD burden.

The audience take away from presentation:
This abstract assesses the impact of pneumococcal conjugate vaccine on antibiotic-resistant serotypes in 321 invasive S. pneumoniae isolates among the hospitalised children detected over a 15-year period in our population-based surveillance for pneumonia, sepsis, and meningitis in rural Gambia. This abstract demonstrates a significant decline in antibiotic-resistant vaccine-type pneumococcal serotypes, coupled with an increased prevalence of non-vaccine types, notably serotype 12F, with a relatively stable resistance pattern across individual antibiotics for all serotype and therefore, adoption of higher valent PCVs containing 12F is needed to reduce IPD burden.