USC researchers identify symptoms associated with increased risk for long COVID

The absence of strict diagnostic criteria is also a major issue for patients attempting to seek treatment. At the moment, long COVID is considered an “exclusionary diagnosis,” meaning one that is given only after all other valid possibilities have been ruled out, said Melissa Pinto, an associate professor of nursing at UC Irvine who studies the condition. In the U.S., that can mean a long and expensive process of submitting to various tests and specialists.