BOZEMAN — An 11th case of measles was confirmed on Thursday, June 5th, according to the Gallatin City-County Health Department website.

The case is a "known exposure from a previous case."

The department listed the active public exposure points as

• 6/3/2025 Ramirez Mexican Food - 319 No. 7th Ave. Bozeman - Monitor for symptoms through June 24, 2025
• 6/3/2025 On Mission Thrift - 425 No. 7th Ave. Bozeman - Monitor for symptoms through June 24, 2025
• 6/3/2025 Cash 4 Clothes - 119 No. 7th Ave - Monitor for symptoms through June 24, 2025
• 6/2/2025 Town & Country - 1611 So. 11th Ave. Bozeman - Monitor for symptoms through June 24, 2025
• 6/1/2025 Ace Hardware - 26 E. Main St., Bozeman - Monitor for symptoms through June 24, 2025

There are now 19 cases of measles reported in Montana, in three counties: Flathead (2), Hill (4), and Gallatin (11), according to the state.

On May 23, 2025, Hill County Health Department issued enhanced Measles, Mumps, and Rubella (MMR) vaccination recommendations for all residents and travelers to Hill County due to the potential for community transmission. The recommendations include early and accelerated vaccination for children and an additional MMR dose for adults who have received one dose. Currently, early and accelerated vaccination is not recommended for residents or travelers to other Montana counties.

Measles have also been reported in surrounding states and provinces:

Measles is highly contagious, spreading rapidly among those without immunity. According to the Montana Department of Health & Human Services (DPHHS), “If somebody with measles walks into a room, 90% of people who have no immunity to it will get infected.”

Vaccination remains the most effective defense. One dose of the measles vaccine is about 93% effective, while two doses reach approximately 97% efficacy. Health officials warn that a recent decline in vaccination rates is largely responsible for the current outbreak.

“It’s been 35 years since we had a reported measles case in the state,” says Laura Williamson a State Epidemiologist with Montana DPHHS.

The number of measles cases in the U.S. this year is nearing a 30 year high.

That number has quadrupled compared to 2023. As of Friday, according to the CDC, there have been 1,168 confirmed cases across 33 states nationwide. Most cases are in unvaccinated people.

There are also new challenges to addressing the spread of measles: according to a Johns Hopkins University study published this week, rates of childhood vaccination against measles fell broadly across the U.S. in the wake of the COVID-19 pandemic.

Childhood vaccination for measles dropped in close to 80% of counties, according to available data for more than 2,000 counties nationwide. The decline includes states that are actively battling outbreaks of the disease.

Domestic and international travel both contribute to the spread of the disease, experts say. U.S. health officials in June directed Americans to get vaccination against measles if they were participating in international travel, no matter their destination or itinerary.

Three people have died in 2025's national outbreak.

The outbreak also threatens to reverse measles' formal elimination in the U.S. If the outbreak continues until January of 2026, measles will no longer be considered eliminated — a designation that requires 12 months with no local transmission of the disease.

Additional reporting by Scripps News Group