Pneumococcal Serotype Prevalence in Southeast Asia: A Systematic Review and Meta-Analysis

BackgroundThe prevalence of Streptococcus pneumoniae serotypes in the ASEAN region is not well studied despite severe pneumococcal infections being a major cause of death among children in the region. This information is crucial for understanding the epidemiology of the disease and guiding vaccine policies. Our study aimed to provide a thorough analysis of the pneumococcal serotypes in ASEAN prior to vaccine introduction to assist countries in formulating evidence-based vaccine policies. MethodsWe conducted a systematic review and meta-analysis of studies reporting S. pneumoniae serotypes from carriage, invasive disease (IPD) and non-invasive disease (non-IPD) published up until 31st December 2022 using PubMed, PubMed Central, Ovid MEDLINE and Scopus databases, reference lists and search engines. Data prior to the national introduction of conjugate vaccines in the ASEAN region were included. Non-English, animal, case studies, reviews, and studies on antibiotic resistance only were excluded. The quality of studies was examined using the CASP and the JBIs Critical Appraisal Tools. The frequency of serogroups and serotypes was calculated, and vaccine coverage was estimated by the addition of vaccine serotypes as a fraction of the total number of isolates per age group. This study was registered with PROSPERO CRD42022243994. FindingsA total of 940 studies were identified, and 99 and 84 relevant papers were included in the qualitative and quantitative analyses, respectively. A total of 16,396 isolates were identified, spread across all body sites and ages, with vaccine-covered serotypes 19F (n = 2,061, 12.57% [95%CI: 12.07 - 13.09]), 23F (n = 1,508, 9.20% [95%CI: 8.76 - 9.65]) and 6B (n = 1,160, 7.07% [95%CI: 6.69 - 7.48]) occurring most often. Non-vaccine types e.g., 6AB (n = 617, 3.76% [95%CI: 3.48 - 4.07]), 15BC (n = 35, 2.57% [95%CI: 2.33 - 2.82]) and 34 (n = 260, 1.59% [95%CI: 1.40 - 1.79]) were also frequently observed. InterpretationThe most common serotypes found in IPD, non-IPD, and carriage in ASEAN are covered by currently available conjugate vaccines. This underscores the importance of vaccination and predicts future success in reducing the burden of pneumococcal disease. The data gathered offers important insights into pneumococcal serotype epidemiology across the different countries belonging to ASEAN.