RSV is on the rise nationwide, and doctors in New Jersey say they are seeing the illness much earlier this season.

RSV mostly causes cold-like symptoms, but in young children it can be a lot worse. Dr. Harpreet Pall, the pediatrics chair at Hackensack Meridian Hovnanian Children's Hospital at Jersey Shore Medical Center, says it's concerning to see the illness take hold so early.

"The timing is unusual because we usually see a winter peak for RSV, but this started a few months ago and now the cases are starting to rise," says Pall.

Doctors say the COVID pandemic is to blame for the increase in cases.

"During the pandemic, children may not have been exposed to the number of viruses they typically are exposed to," says Pall. "Many were at home, so their immune systems didn't have a chance to develop immunity to some of the more common viruses."

Pall says parents should look out for symptoms like heavy and fast breathing, high fever and dehydration. He says that's when parents should call their pediatrician.

Doctors say regular hand-washing, social distancing and staying home if you are sick can help stop the spread.