NISKAYUNA, N.Y. (NEWS10) — More than a dozen toddlers who attend Pooh’s Corner in Niskayuna are sick. Three of them are in the hospital after a virus spread through the pre-school.

The school said it has strict cleaning rules and a health care professional to check on the toddlers daily, but the potentially deadly Respiratory Syncytial Virus (RSV) still spread among its kids.

“It’s basically an upper respiratory infection. So it is a cold and a flu, at the same, but it attacks childrens’ lungs. So that’s where it could become difficult for them,” said Executive Director Meredith Janke.

The school will close Friday to get a hold on the virus.

“In my experience as a teacher and as an administrator, I’ve never had anything like this before,” Janke said.

While the school is shut down, staff will do a deep cleaning.

“It’s just a big variety of so many sicknesses that it’s just created this big germ, and we somehow  have to get rid of it,” said Assistant Director Duane Hotaling.

Parents at the day care said they’re happy the daycare is closing down to clean the building.

“If it’s going to control the virus, you know, like anything else, I’m for it,” said parent Kelsey Holland.

The Mayo Clinic calls RSV common. It also said “most people recover in a week or two, but RSV can be serious, especially for infants and older adults.”