The Wyoming Department of Health reported a positive measles case in an unvaccinated adult on June 28 in Teton County. The state’s first case this year was detected in an adult in Fremont County in May.
Fifteen cases were reported in the state last year, though none were in Teton County. Before the 2025 outbreak, the state had not detected any cases in 15 years.
The person in Teton County may have exposed others to the sickness at a few places in Grand Teton National Park: between noon and 10 p.m. on June 17 or 18 at Cafe Court Pizzeria and Ranch House Restaurant in Colter Bay Village and between 2 p.m. and 4 p.m. on June 20 at the Colter Bay Convenience Store. They also may have exposed others at Target in Jackson on the morning of June 25.
The highly contagious infection can linger in the air for up to two hours after the infected person leaves. Symptoms include a rash spreading down the body, a fever, cough, or runny nose.
2025 marked a 30-year high in measles cases across the U.S. (Screenshot / U.S. Centers for Disease Control and Prevention)
Anyone who was exposed is at risk of contracting measles, which is one of the most infectious diseases known. It can be life-threatening for infants, pregnant people and the immunocompromised.
“We are asking people who may have been exposed to watch for measles symptoms for 21 days past the exposure date and consider avoiding crowded public places and high-risk settings such as daycare centers,” State Health Officer Dr. Alexia Harrist said in a press release.
A community can achieve protection for most people through herd immunity if more than 95% of the population is vaccinated, according to the U.S. Centers for Disease Control and Prevention (CDC).
Vaccination coverage among Wyoming kindergartners is estimated at 93.6% for 2024-2025 school year, according to the CDC. That number across the U.S. decreased from 95.2% during the 2019–2020 school year to 92.5% in the 2024–2025 school year.
