MADISON, Wis. — A measles outbreak is ongoing in southwest Wisconsin, with more than a dozen cases confirmed in the region and additional tests pending.
The Department of Health Services says the case count in Iowa and Lafayette Counties up from two to 15 confirmed and six probable as of the morning of August 13.
While a specific public health exposure has not been determined, Dr. Ryan Westergaard says the cases are believed to have been exposed in Wisconsin, suggesting there may be additional measles cases in communities that have not yet been identified. DHS confirmed there is active local transmission, meaning there are likely more cases which exist in the community that have not yet been reported.
“The rapid emergence of these cases, particularly among people who have not travelled outside of Wisconsin, indicates that there is active local transmission,” said Chief Medical Officer for DHS’s Bureau of Communicable Diseases Dr. Westergaard in a news conference August 13.
Of the 23 measles cases reported so far in Wisconsin this year, Dr. Westergaard says nearly 96% have been among unvaccinated people. The outbreak comes the same week as President Donald Trump announced an executive order calling for separating combination shots — including the measles, mumps and rubella, or MMR, vaccine — into separate injections.
“We are deeply concerned about the lack of scientific evidence in statements from top federal officials, and potential implications for the health of children in our state,” said DHS Secretary Kirsten Johnson in a statement. “Health professionals and parents deserve accurate, credible information. There is no new scientific evidence that justifies changing recommendations that have, and continue to, protect children across the United States.”
In Iowa County, roughly 81 percent of two-year-olds received one or more doses of an MMR vaccine in 2025 and about 60% did in Lafayette County, according to data from DHS. That compares to the state average of just under 80% of all Wisconsin two-year-olds; overall the state rate has trended down from about 88 percent in 2013. For those born in or after 1989, DHS recommends if you received only one dose and are school aged, or if you work in health care, are a college student, or are planning to travel internationally, you should receive a second dose.
In 2025, there were 36 measles cases confirmed statewide.
Measles is a highly contagious disease that can be spread from person to person through the air and can stay in the air for two hours after a sick person coughs or sneezes. Measles can cause serious health complications, including pneumonia, brain damage, and deafness, and can sometimes be deadly.
One in four people who get measles in the United States will be hospitalized, though Dr. Westergaard confirmed none of the people infected in the Wisconsin outbreak have been hospitalized.
Residents should know the symptoms of measles and call a health care provider if they develop symptoms, even if they are not aware of a specific exposure. Symptoms of measles typically appear approximately 10 to 21 days after being exposed to the virus, and include:
- Runny nose
- High fever (may be greater than 104°F)
- Tiredness
- Cough
- Red, watery eyes, or conjunctivitis (pink eye)
- A red rash with raised bumps that starts at the hairline and moves to the arms and legs three to five days after symptoms begin
Anyone developing symptoms of measles should stay home (not go to work, school, social gatherings, shopping, or use public transportation) and call a doctor’s office or clinic before visiting so they can take precautions to ensure other patients are not exposed to the virus.
This is a breaking news story; more information will be added as it becomes available.
