Poster Presentation 20th Lancefield International Symposium on Streptococci and Streptococcal Diseases 2017

Low prevalence rates for group A β-Haemolytic Streptococcal Carriage in Africa: A Cross-Sectional Study and Systematic Review (#234)

Mark E Engel 1 , Hlengiwe Moloi 1 2 , Leila Abdullahi 1 , Dylan D Barth 1 , Bongani M Mayosi 1
  1. AFROStrep Research Initiative, University of Cape Town, Observatory, WC, South Africa
  2. Health Systems Research unit, Medical Research Council, Tygerberg, South Africa

Background: Asymptomatic children can be a major reservoir of pharyngeal Group A Streptococcus (GAS). There is a need to document GAS carriage, so as to inform the development of putative GAS vaccines. We, therefore, undertook to perform a cross-sectional study to determine the prevalence of GAS carriage in school children in Cape Town;  we considered our results in the context of a meta-analysis of pooled data of GAS carriage in school children residing in African countries.

Methods:  Pharyngeal swabs were obtained from learners in Cape Town and processed at the microbiology facility at Groote Schuur Hospital.  Thereafter, we conducted a systematic review through a comprehensive literature search among several sources. Prevalence estimates with 95% CIs were determined using a random-effects meta-analysis.

Results: GAS was isolated from 31/950 healthy learners (3%;  95%CI, 2%-4 %) enrolled from 2009-2011. Together with 18 studies meeting our systematic review inclusion criteria, the pooled prevalence was 9% (95% CI, 6% to 11%;  19 studies). Sub-analyses revealed similar pooled rates across Southern, Eastern and Northern Africa.  Countries within Central Africa and West Africa had notably lower estimates of <8%. 

Discussion: Our cross-sectional study reports a low prevalence of GAS carriage in South African school children.  Across Africa, pooled results reveal a GAS carriage estimate of 9%, lower than the 12% reported in an earlier systematic review. Given that, studies of pharyngitis report GAS prevalence of >20%, our findings emphasize the association between GAS and pharyngitis.