WASHINGTON (AP) — A U.S. study suggests 1 in 10 people are getting long COVID after an omicron infection, a lower estimate than earlier in the pandemic.

The National Institutes of Health is studying nearly 10,000 U.S. adults to help better understand why some people suffer debilitating health problems that can last for months or years after even mild COVID-19.

In the Journal of the American Medical Association, researchers identified a dozen key symptoms that help distinguish long COVID.

They say doctors shouldn’t use the list to diagnose patients — it’s only a first step — but it might help future studies.