The number of flu cases is spiking just as kids are returning to school from winter break, and school officials urge parents to keep sick children at home.
Doctors recommend that kids who haven't fully recovered from the flue or seem like they're becoming sick should not go to school. They also suggest reminding kids to frequently wash their hands and not share food or drinks.
"The biggest risk to getting the flu is being exposed to the flu," Highland Park Emergency Center's Jeff Erdner said. "Schools are an area where everyone keeping those kids home will be the most helpful."
Even those who received a flu shot are susceptible, as Centers for Disease Control and Prevention officials said this year's shot is less effective because of a virus mutation.
Officials with several school districts told NBC 5 that they have cleaning crews disinfect the schools daily, especially areas like drinking fountains and doorknobs.
"Washing your hands, covering your mouth whenever you cough and sneeze, all those are habits that have been taught to the children," Daffron Elementary School principal CIndy Guinn said. "Our custodians do a great job keeping our building clean. And teachers remind students daily to use their anti-bacterial."
