Group A Streptococcus Disease Outbreak Associated with Large Congregate Shelter, Chicago, Illinois, USA, October 2023-January 2024.

Chicago Department of Public Health identified 3 pediatric patients hospitalized with group A Streptococcus (GAS) disease during October 26-November 3, 2023, in a large congregate family migrant shelter in Chicago, Illinois, USA. One patient had invasive GAS infection; 2 had peritonsillar abscesses requiring drainage. Despite infection control measures, GAS pharyngitis cases continued through November 13. Chicago Department of Public Health coordinated clinical partners to perform rapid antigen detection testing and throat cultures for residents and staff with pharyngitis symptoms. During November 20, 2023-January 3, 2024, a total of 428 symptomatic persons were evaluated; 166 tested positive for GAS. Among persons with GAS pharyngitis, median age was 12 years (range 0-45 years); 54.2% were women and girls. Common symptoms included sore throat (87.3%) and fever (63.3%). One pediatric resident death caused by invasive GAS was confirmed postmortem. This response highlights outbreak challenges in large congregate shelters housing children.