On Jun. 11, 2025, the Montana Department of Public Health and Human Services (DPHHS) reported a total of 20 cases of measles and two hospitalizations in state residents to date. Newly identified cases are isolating. The 20 cases have been reported from the following jurisdictions in Montana: Flathead (2), Yellowstone (2), Hill (4), and Gallatin (12).

Individuals who are immune to measles through vaccination, laboratory evidence of immunity, laboratory confirmation of disease, or were born before 1957 are not considered at risk for infection.

Individuals without prior measles infection or vaccination have a 90% likelihood of contracting the disease if exposed.