Before and after the bottleneck: pediatric group A streptococcal infections in Houston, TX, from 2013 to 2023

Toward the end of the COVID-19 pandemic, many reports described increasing group A streptococcal (GAS) infections. We sought to describe pandemic-associated changes in GAS clinical and molecular epidemiology. GAS isolates were collected from Texas Children's Hospital laboratory from 01 January 2013 to 31 December 2023 and grouped into pre-pandemic (2013-2019) and pandemic (2020-2023) periods. Invasive (INV), skin and soft tissue infection (SSTI), and pharyngeal (PHG) disease types were determined by medical record review. All isolates were emm typed, and nonsusceptibility (NS) to tetracycline, erythromycin, and clindamycin was determined using standard methods. We analyzed 2,717 isolates (pre-pandemic, n = 1,640; pandemic, n = 1,077). Year-to-year variation was observed, but the highest GAS disease burden occurred in 2022 and 2023. Comparing disease types, we observed a subtle but significant increase in the frequency of GAS strains derived from INV infections. Relative to pre-pandemic, emm12 and emm3 GAS showed significant increases in frequency, while emm89, emm4, and emm6 showed concomitant decreases. Second-line antimicrobial NS increased during the pandemic period but was transient with a rapid return to pre-pandemic rates in 2023. The pandemic-related surge in GAS disease in the Houston, TX, pediatric population was associated with changes in the frequency of GAS emm types and a small shift toward invasive disease. NS to second-line antimicrobials fluctuated during the pandemic and differed substantially from GAS derived from adult infections. Continued surveillance will be paramount to monitor ongoing changes in GAS epidemiology in pediatric populations.

Group A Streptococcus (GAS) causes common childhood infections such as strep throat but can also lead to severe, life-threatening disease. During and after the COVID-19 pandemic, many regions reported sharp increases in GAS infections, yet the reasons for these changes were unclear. Using long-term surveillance of children in a large US city, this study shows that the post-pandemic rise in GAS was accompanied by meaningful changes in both the types of infections and the strains causing them. We found a small but significant increase in invasive disease, shifts in the most common GAS strain types, and temporary increases in resistance to certain antibiotics. These changes likely reflect how pandemic-related disruptions altered bacterial spread. By examining both mild and severe infections over more than a decade, this work demonstrates how large-scale changes in human behavior can reshape bacterial disease patterns and highlights the importance of continued monitoring to protect child health.