The burden of group A streptococcal pharyngitis in Melbourne families

Abstract

Background & objectives: There are no recent data from industrialised countries documenting the incidence and costs of group A streptococcal (GAS) pharyngitis. Such data are important in developing policy regarding management (e.g., whether or not to use antibiotics to treat sore throat) and in planning preventive strategies, including preparing for the arrival of GAS vaccines. The present study was undertaken to estimate the incidence and costs of GAS pharyngitis in school aged children in Melbourne, Australia. We report here the results after initial 11 months of surveillance.

Methods: A total of 202 families (852 individuals) with at least one child aged 3 to 12 yr were enrolled across Melbourne in a family-based cohort study, and are being followed prospectively for 24 months. Surveillance data for acute GAS pharyngitis (including serology), throat carriage, and costs of the disease were collected. Additional cases of GAS pharyngitis have been ascertained to improve the precision of costing estimates.

Results: Cohort retention was 97 per cent. The spring, summer and winter carriage rates for children were 13.0, 8.0 and 16.0 per cent respectively. The incidence of GAS pharyngitis was 14 per 100 person-years for children. For every primary case there were 0.7 secondary cases and 24 per cent of families experienced at least one episode of GAS pharyngitis per year. Preliminary costing data suggest that 46 per cent of cases lead to school absenteeism and a high rate of antibiotic use.

Interpretation & conclusion: The present data suggest that GAS pharyngitis remains very common in childhood, and that it has further implications in terms of secondary cases and costs.