Finally, the hunt for answers about long COVID is yielding some clues.

A new study, led by the Icahn School of Medicine at Mount Sinai and the Yale School of Medicine and published in Nature, defines some critical differences in certain biomarkers of people with long COVID. The next step is even more critical: coming up with a way to cure them.

A massive number of people in the U.S. are dealing with lingering symptoms. Two new reports from the Centers for Disease Control and Prevention found that in 2022, some 18 million adults said they had ever had long COVID, with about 8.8 million currently suffering from the condition. In that time, roughly 1 million children had been affected — with about 360,000 children reporting an ongoing case.