Study Finds Sharp Rise in Dangerous Strep Infections

TUESDAY, April 8, 2025 (HealthDay News) -- Severe and possibly deadly strep infections are on the rise in the U.S., a study published Monday in Journal of the American Medical Association said.

The rate of invasive group A strep infections more than doubled from 2013 to 2022, jumping from about 4 cases per 100,000 people to 8 per 100,000, NBC News reported.

These infections happen when strep bacteria spread to normally germ-free parts of the body, such as the lungs or bloodstream. 

Unlike regular strep throat, this type can lead to dangerous conditions like necrotizing fasciitis (flesh-eating disease) or toxic shock syndrome.

“Within 24 to 48 hours, you could have very, very rapid deterioration,” Dr. Victor Nizet, a professor of pediatrics at the University of California, San Diego, told NBC News. Cases can transition from "seeming like a routine flu-like illness to rushing the patient to the ICU, fearing for their recovery,” he added.

The U.S. Centers for Disease Control and Prevention (CDC) tracked data from 10 states with about 35 million people.

In 2013, there were 1,082 cases. By 2022, there were 2,759 cases. In all, more than 21,000 cases were recorded over the period, including nearly 2,000 deaths, NBC News said.

“When you see this high number of deaths, extrapolate that across the country — we’re probably well into more than 10,000 deaths,” Nizet said.

Dr. Christopher Gregory, a CDC researcher and co-author of the study, said invasive strep now poses a higher threat to both high-risk groups and the general population.

The rise may be linked to several issues: For one, more people are living with diabetes or obesity, which weakens the immune system. 

There's also been a rise in infections among people who inject drugs or experience homelessness. In 2022, the rate of infection among homeless people was 807 per 100,000 — one of the highest ever recorded, NBC News said.

Gregory said the rate was “among the highest ever documented worldwide.”

Also, strep strains are changing. New strains seem to cause more skin infections, not just sore throats, and some are becoming resistant to antibiotics like macrolides and clindamycin.

The infection rate was highest among adults 65 and older, and all adults saw increases. Surprisingly, though, the study didn’t find an overall increase in children, but doctors say they’re seeing more serious cases.

“That was, to me, the most shocking part of the study,” said Dr. Allison Eckard, division chief for pediatric infectious diseases at the Medical University of South Carolina. “Because clinically, we really are seeing what feels like an increase."

Eckard, who reviewed the findings, said doctors are seeing more severe and more unusual cases, as well as more necrotizing fasciitis. It all raises concern, she said, that and cases "there is something going on more nationally.”

She and other experts say more research is needed to understand what’s causing the rise and whether strep strains are becoming more dangerous. 

They also say a vaccine is badly needed, but progress may be slow due to recent changes at the U.S. Food and Drug Administration (FDA).

“The lack of vaccine is devastating,” Nizet concluded. “Of course, we’re concerned about the turn of attitudes at the FDA and the CDC that seem to be putting some sticks in the spokes of the wheel of vaccine development.”

More information

There's more about Group A strep infection at the U.S. Centers for Disease Control and Prevention.

SOURCE: NBC News, April 7, 2025

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