Introduction
Invasive Group A streptococcus (iGAS) infection can be serious and life-threatening. Response to the COVID-19 pandemic has caused significant changes in social contact patterns, healthcare access and delivery of public services. We aimed to describe the impact of the COVID-19 pandemic on the current epidemiology of iGAS in England.
Methods
All iGAS isolates referred to the English streptococcal reference laboratory between the 01-01-2016 to 31-12-2021 characterised by emm typing were included. Data were analysed by period (pre-pandemic 01-01-2016 to 31-03-2020, pandemic 01-04-2020 to 31-12-2021) and emm type using counts, proportions, median and percentage change. Annual diversity was estimated using Simpson’s index.
Results
Data from the 10,408 sterile infections indicated that the median cases/month were reduced and emm type diversity increased year-on-year from 2018 (208, 0.77) to 2021 (66, 0.46). The emm with the largest percentage change (pre to pandemic) were 1.0 (-8.9%), 108.1 (+6.8%), 77.0 (+4.2%) and 66.0 (+3.0%). Pre-pandemic emm 1.0 was largely dominant (21%, 1757/8253) but has now fallen (12%, 268/2155) and 108.1 (pre: 194, 2.4% and post: 198, 9.2%) increased. Cases infected with emm 66, 77, and 108.1 during the pandemic were younger, male and have injecting drug use recorded.
Discussion
We identified case reduction and shift in the epidemiology of iGAS in England. The increase in proportion of emm 66,77 and 108.1 and demographic change indicates that marginalised groups remain affected by iGAS. We recommend further work is undertaken to understand the changing epidemiology and interventions, such as early identification and management of wounds, are targeted towards affected groups.