Publication date: May 28, 2025

An unexpected surge in severe Group A Streptococcus (GAS) infections occurred during 2022-2023. We assessed changes in the epidemiology and clinical characteristics of severe GAS infections during and after the COVID-19 pandemic. We analyzed severe GAS infections in children admitted to a university hospital in Paris, France (2018-2023). Proven and probable invasive GAS (iGAS and piGAS) cases were included. Using time-series analysis, we modeled the incidence of severe GAS infections across 4 periods: prepandemic, early pandemic, late pandemic and postpandemic. Infection characteristics were also compared between periods. We included 269 children with severe GAS infections (mean age 4. 0 +/- 4. 0 years), including 92 iGAS cases. Most cases were severe ear-nose-throat (ENT) infections (192/269, 71%), followed by bone and joint infections (10%) and pleural empyema (8%). In the early pandemic period, GAS infections decreased by 83% [incidence rate ratio (IRR) 0. 17 (95% CI: 0. 10-0. 27)], but increased significantly in the late pandemic period [IRR 1. 65 (95% CI: 1. 22-2. 24)]. Postpandemic incidence returned to prepandemic levels [IRR 0. 97 (95% CI: 0. 68-1. 38)]. Compared to other periods, late pandemic cases were more severe, with longer hospital stays (9. 4 vs. 6. 4 days; P = 0. 0007), more iGAS forms (47% vs. 28%; P = 0. 001), increased proportions of pleural empyema (15% vs. 4%) and bone and joint infections (14% vs. 7%; P = 0. 008), and more complicated ENT infections (22% vs. 7%; P = 0. 003). The late COVID-19 pandemic period was marked by a rise in both the incidence and severity of GAS infections. These findings may improve preparedness in future pandemics.

Semantics

Original Article