The prevalence of Group A Beta-Hemolytic Streptococci carriage in children in Africa: a systematic review

Abstract

Asymptomatic children can be a major reservoir of pharyngeal Group A Streptococcus (GAS) with reported figures ranging from <10% to >20% in developing countries. There is a need to document GAS carriage in school children, which, together with the molecular characterisation (M-typing) of strains harboured in the pharynx of carriers, will help to ascertain the extent to which disease strains are prevalent amongst carriers. This background information would serve to assist healthcare providers in diagnosing symptomatic GAS pharyngitis, as well as could potentially contribute to the development of a GAS vaccine. Currently, data on GAS carriage prevalence and M-type distribution in African countries are largely scant. We therefore undertook to perform a systematic review to determine the prevalence and type distribution of asymptomatic streptococcus carriage in children aged 5 -15years, residing in African countries. Methods: We conducted a comprehensive literature search among a number of databases, using an African search filter to identify GAS prevalence studies that report on children between the ages of 5 - 15 years who reside in African countries. Electronic searches were complemented by a hand search performed on reference lists of potentially included studies. The search was not limited by year of publication and language. Two evaluators independently reviewed, rated, and abstracted data from each article. Prevalence estimates were pooled in a meta-analysis and stratified according to region and study design using Stata®. Specifically, we applied the random effects metaprop routine to aggregate prevalence estimates and account for between study variability in calculating the overall pooled estimates and 95% CI for GAS carriage prevalence.