It's the largest outbreak of chicken pox in the country.

Listen:

Approximately 85 cases of chicken pox have been reported in Vigo County, but health officials are worried that as many as 100 kids could be infected by the end of the week.

The outbreak isn't contained to Vigo County either, 8 children in Parke County have also been infected, according to Sydney Elliott with the Vigo County Health Department.

Elliott says a lot of the children coming down with chicken pox were vaccinated, but occasionally a strain of the chicken pox virus can mutate, rendering the vaccine a lot less effective.