NEW YORK (AP) — Health experts once thought 2020 might be the worst year yet for a rare paralyzing disease that has been hitting U.S. children for the past decade.

But they now say the coronavirus pandemic could disrupt the pattern for the mysterious illnesses, which spike every other year starting in late summer.

Scientists say it’s possible that mask wearing, school closures and others measures designed to stop spread of the coronavirus may also hamper spread of the virus suspected of causing the paralyzing disease.

The pandemic is dominating public health work right now, but officials are trying to draw attention to the polio-like condition they call acute flaccid myelitis, or AFM. The U.S. Centers for Disease Control and Prevention on Tuesday made a public call for parents and doctors to watch for it, and act.

Hundreds of U.S. children have developed AFM since 2014. Most had a cold-like illness and fever, seemed to get over it, then descended into paralysis. In some cases it started small — for example, a thumb that suddenly wouldn’t move. Some children went on to lose the ability to eat or breathe.