The epidemiology of repeatedly positive bacterial skin infections in Auckland children, New Zealand

Abstract

Objective: Māori and Pacific New Zealanders are disproportionately affected by Acute rheumatic fever (ARF) and rheumatic heart disease (RHD). Repeated S. pyogenes skin infections in childhood are thought to increase the risk of developing ARF/RHD. This study investigated the epidemiology of repeated bacterial skin infections within Auckland, New Zealand. Method: Microbiology results from wound swabs collected in primary care between 2010 and 2020 were used to estimate the rate of repeatedly positive infections, along with rate ratios and 95% CIs, across demographic groups. Results: S. aureus infections impacted all groups; but Māori (Rate Ratio: 10.0, 95% CI: 8.5–11.6) and Pacific children (Rate Ratio: 14.6, 95% CI: 12.6–17.0) under 10 years of age were at a greater risk of repeated S. pyogenes infections compared to their non-Māori/non-Pacific counterparts. The relative risk of subsequent S. pyogenes infection was 4.1 times higher (95% CI: 4.0–4.3) following an initial S. pyogenes infection compared to those negative for S. pyogenes. Conclusion: Māori and Pacific children's heightened vulnerability to repeated S. pyogenes skin infections supports the immune priming theory of ARF/RHD. Targeted public health initiatives, primary care interventions and Group A Streptococcal vaccine are crucial to reduce repeated S. pyogenes exposure and potentially lower ARF risks.