• Posted October 2, 2025

Kids' Long COVID Risk Doubles After Second Infection, Researchers Say

THURSDAY, Oct. 2, 2025 (HealthDay News) — Children and teens have a doubled risk of long COVID following their second COVID-19 infection, researchers report.

What’s more, long COVID dramatically increases kids’ risk of myocarditis, blood clots, damaged kidneys, abnormal heart beats and other health problems, researchers report in The Lancet Infectious Diseases.

“The results of this study further support one of the strongest reasons I give patients, families and physicians about getting vaccinated: More vaccines should lead to fewer infections, which should lead to less long COVID,” researcher Dr. Ravi Jhaveri, head of pediatric infectious diseases at Ann & Robert H. Lurie Children's Hospital of Chicago, said in a news release.

For the study, researchers analyzed the health records of more than 465,000 children and teens from Jan. 1, 2022, to Oct. 12, 2023, during the Omicron wave of the COVID pandemic.

All of those children had an initial COVID infection, and more than 58,400 went on to have a second infection, researchers said.

Results showed that reinfection doubled a child’s risk of later diagnosis for long COVID.

Subsequently, kids diagnosed with long COVID had a tripled risk of myocarditis, a swelling of the heart muscle than can weaken the heart, researchers said.

Long COVID children also were more than twice as likely to develop blood clots, and were at increased risk for many other health problems associated with the syndrome, the study says.

The results run counter to popular perceptions that COVID in children is mild, and that reinfections don’t carry the same risk of long COVID that initial infections do, researchers said.

Moving forward, researchers plan to track data on children and teens over longer periods. They also want to examine whether newer COVID variants change long COVID risk patterns, and explore specific strategies that might ward off long-term health problems.

More information

The Cleveland Clinic has more on long COVID in kids.

SOURCES: Ann & Robert H. Lurie Children's Hospital of Chicago, news release, Sept. 29, 2025; The Lancet Infectious Diseases, Sept. 30, 2025