Prevalence of group A β-hemolytic streptococcal throat carriage and prospective pilot surveillance of streptococcal sore throat in Ugandan school children.

Objectives: Group A β-hemolytic Streptococcus (GAS), also known as Streptococcus pyogenes, is responsible for an annual 600 million cases of acute pharyngitis globally, with 92% of those infections occurring in low-resource settings. Further knowledge of the acute streptococcal pharyngitis burden in low-resource settings is essential if serious post-streptococcal complications - rheumatic fever (RF) and its long-term sequel rheumatic heart disease (RHD) - are to be prevented.

Methods: Two studies were conducted in school-aged children (5-16 years): a cross-sectional study of streptococcal pharyngeal carriage followed by a prospective cohort study of streptococcal sore throat over 4 weeks from March to April 2017.

Results: The cross-sectional study revealed an overall prevalence of GAS carriage of 15.9% (79/496, 95% confidence interval 12.8-19.5%). Among 532 children enrolled in the prospective cohort study, 358 (67%) reported 528 sore throats, with 221 (41.1%) experiencing at least one GAS-positive sore throat. The overall GAS-positive rate for sore throat was 41.8% (221/528).

Conclusions: The GAS pharyngeal carriage rates seen in Uganda (15.9%, 95% confidence interval 12.8-19.5%) are higher than the most recent pooled results globally, at 12% (range 6-28%). Additionally, pilot data suggest a substantially higher percentage of sore throat that was GAS-positive (41.8%) compared to pooled global rates when active recruitment is employed.