Cases of invasive group A strep are on the rise in the U.S., according to a newly published report led by CDC researchers.
From 2013 to 2022, the rate of infections rose from 3.6 cases per 100,000 people to 8.2 cases per 100,000, according to the study, published April 7 in JAMA Network. The report is based on surveillance data from 10 states that track the infections. Overall, researchers identified 21,312 cases during the study period, including nearly 2,000 deaths.
Three notes:
- Severe strep A infections occur when bacteria enter the blood stream and cause invasive infections, which can trigger pneumonia, cellulitis, necrotizing fascitis and streptococcal toxic syndrome. Children’s hospitals across the U.S. saw a spike in cases of invasive strep at the end of 2022, which the CDC linked to the surge in respiratory viruses at the time.
- From 2013 to 2022, the rate of severe strep infections was highest among adults 65 and older. The study did not find an increased rate among children — a surprise to pediatric infectious disease specialists.
“That was, to me, the most shocking part of the study,” Allison Eckard, MD, division chief for pediatric infectious diseases at the Medical University of South Carolina in Charleston, told NBC News in response to the new report. “Because clinically, we really are seeing what feels like an increase.” - Several factors may be driving the rise in infections, the researchers said. These include an increasing number of people with underlying conditions such as diabetes and obesity, which can impair immune function or cause skin breakdown. The study also cites higher rates of infection among people who inject drugs, those experiencing homelessness and residents of long-term care facilities. In addition, researchers noted a substantial increase in antibiotic resistance — with more than one-third of isolates in 2022 nonsusceptible to macrolides or clindamycin, up from 13% in 2013.
