Source: New Zealand Ministry of Health
Summary
Group A streptococcus (GAS) bacteria is a pervasive pathogen, spread through airborne droplets and skin-to-skin contact, that may lead to invasive group A streptococcus (iGAS), post-streptococcal glomerulonephritis (PSGN), acute rheumatic fever (ARF) or rheumatic heart disease (RHD). The onset of iGAS is often sudden, and the disease progresses rapidly. It can result in serious health outcomes such as loss of limbs or severe scarring, brain damage, hearing loss or learning disabilities. Without timely treatment, sepsis can rapidly lead to tissue damage, organ failure and death.
People with socio-economic disadvantage are at greater risk of GAS and iGAS infections; the prevalence of GAS infections is commonly associated with low-quality and inadequate housing. Lack of access to clean water, homelessness and drug injection are other contributing risk factors.
Physiologically, the role of GAS infections in pharyngitis is well understood, likely because of its role in the sequalae of ARF. However, there is increasing recognition of the role of GAS skin infections in the development of iGAS, ARF, RHD and PSGN.
Since 2022, the number of iGAS cases reported has increased internationally, including in New Zealand. Case rates have increased beyond those recorded in 2017 (pre-COVID-19 pandemic), and cases in 2023 showed large ethnic disparities. In 2023, the decision was made to start the process to make iGAS a notifiable disease in New Zealand. The Deputy Director of Public Health commissioned this evidence brief in anticipation of iGAS being made a notifiable disease in 2024.
The brief reports on a systematic review of the prevalence of GAS skin infections in cases of iGAS, ARF, RHD and PSGN. It also reports on a scoping review of the evidence on risk factors and prevention of GAS skin infections and provides an analysis of knowledge gaps within the current evidence to inform future research priorities.
