Invasive group A streptococcal infections: lessons learned from the 2022-23 upsurge

During the late phase of the COVID-19 pandemic, several high-income countries reported a surge in invasive group A streptococcal (iGAS) infections, with notable paediatric morbidity and mortality. This Review explores three potential drivers of this increase: the role of the COVID-19 pandemic and associated non-pharmaceutical interventions on group A streptococcus (GAS) circulation; the potential burden associated with other respiratory viruses such as influenza and respiratory syncytial virus; and the potential role of hypervirulent GAS clones and lineages. The resurgence of iGAS disease highlights the need for enhanced surveillance of both invasive and non-invasive GAS infections, as well as further research to clarify the role of immunity, viral interactions, and bacterial molecular epidemiology and its evolution. A comprehensive understanding of these dynamics is essential to inform future public health strategies aimed at mitigating the burden of iGAS disease.