Background: Group A streptococcal (GAS) infections can trigger an immune-mediated response resulting in acute rheumatic fever (ARF). The role of social and environmental risk factors for GAS pharyngitis and skin infections are not well understood. This study aimed to investigate what risk factors are associated with GAS pharyngitis and skin infections, and to determine if these are the same as those for ARF.
Methods: A case-control study, including 733 children aged 5-14 years, was undertaken between March 2018 and October 2019 in Auckland, New Zealand. Healthy controls (n=190) and symptomatic cases including GAS pharyngitis (n=210), GAS carriers (n=182), and GAS skin infections (n=151), were recruited. Trained interviewers administered a comprehensive, pre-tested, face-to-face questionnaire.
Results: Multivariate analysis identified strong associations between barriers to accessing primary healthcare and having GAS pharyngitis (adjusted OR 3.3; 1.8-6.0), GAS carriage (aOR 2.9; 1.5-6.0) or a GAS skin infection (aOR 3.5; 1.6-7.6). Children who had GAS skin infections were more likely than all other groups to report living in a crowded home (aOR 1.9; 1.0-3.4), having Māori or Pacific grandparents (aOR 3.0; 1.2-7.6), a family history of ARF (aOR 2.2; 1.1-4.3), or having a previous diagnosis of eczema (aOR 3.9; 2.2-6.9).
Conclusion: Reducing barriers to accessing primary healthcare (including financial restrictions, the inability to book an appointment, lack of transport, and lack of childcare for other children) to treat GAS pharyngitis and skin infections may led to a reduction in ARF rates.