There have been a half dozen recent cases of Whooping Cough reported in McLean County in recent days.
Lisa Slater is a Health Department spokeswoman.
"It's really ranged. We have individuals as young as one month to 21 years of age that have been reported with confirmed cases," said Slater.
Slater said all of the cases had received immunization shots.
"After about five to ten years the protection starts to wane. And that is why there is the booster that adults should be receiving," said Slater.
Slater said it's usual to see cases of the bacteria also known as pertussis as winter comes, but not quite so many at once.
The Health Department recommends handwashing, staying away from people who are coughing, and getting a vaccine or booster shot.