Measles Outbreak in Wisconsin Continues to Grow

Tuesday, August 25th, 2026 -- 11:01 AM

(Hope Kirwan, Wisconsin Public Radio) A measles outbreak in the southwestern corner of Wisconsin continues to grow.

According to Hope Kirwan with Wisconsin Public Radio, as of Friday, the state Department of Health Services has identified 41 confirmed and 7 probable cases across Iowa, Lafayette and Grant counties.

All but one of the people infected with measles in Wisconsin this year have been unvaccinated, according to state data. Just over half of the cases have been in children and teens, while 44 percent are in adults.

State and local health officials are working to stop the highly-contagious virus from spreading further. But that work is being made more complicated by low vaccination rates in some communities.

DHS spokesperson Jennifer Miller said in an email that while the situation remains fluid, “we are seeing confirmed cases in pockets of our communities where individuals are under-vaccinated or unvaccinated.”

“Whenever there are pockets of lower immunization coverage, whether due to geographic location, health care access, or personal reasons, highly contagious viruses can spread quickly,” Miller wrote.

Like the rest of the U.S., childhood vaccination rates have fallen in Wisconsin as parents’ uncertainty, and in some cases skepticism, around vaccines has spread in the wake of the COVID-19 pandemic.

But state data shows some of the southwestern communities have had declining uptake of the measles, mumps and rubella vaccine series well before pandemic. Only 60 percent of two-year-olds in Lafayette County had received one or more of the shots in 2025.

Grant County’s rate was just under 64 percent. Iowa County, where the majority of the recent measles cases have been located, had a rate similar to the statewide average at nearly 81 percent. But it’s still well below the threshold needed to prevent an outbreak at 95 percent.

Feel free to contact us with questions and/or comments.