WAUKESHA, Wis. (CBS 58) - Waukesha County health officials are monitoring Wisconsin’s first confirmed measles case of 2026 as vaccination rates in the county continue to trend downward.

A Waukesha County resident tested positive for measles after an international exposure. Health officials say more than 340 people have been contacted who may have been exposed and they do not expect that number to increase.

Quarantine numbers are declining. Just a few days ago, about 60 people were in quarantine. “Right now, we have 50 people in quarantine, so that’s actually less than yesterday,” Waukesha County Public Health Officer Ben Jones said. “People are in quarantine when they are not vaccinated or they have yet to prove their vaccination.”

The ages of those in quarantine range widely. Jones said, “The ages for those quarantines really do go across the age spectrum. It's anyone who came in contact with that case while they were infectious, so we have a wide range of ages in quarantine.”

According to the Wisconsin Department of Health Services, the statewide vaccination rate among children is 84.8%. In Waukesha County, vaccination rates are higher than the state, but still short of where health officials want them.

Jones said, “Those numbers are between 85–90% which is higher than the state. For measles our goal is 95%. That's really the level of vaccination you need with MMR to stop outbreaks from spreading.”

He added that vaccination rates in the county have changed over time. “In general I would say they have been trending downward slightly over a number of years,” Jones said.

Because exposure was limited, the public risk remains low. Jones said he does not expect any additional exposure-related updates and that the CDC will now take the lead.

Health officials continue to recommend vaccination. “The CDC, DHS, American Academy of Pediatrics all recommend MMR as the only real way to prevent measles,” Jones said.