Utah has become the new measles epicenter in the US, where the epidemic has been ongoing since last summer and has spread across the border into Arizona.[1][3] As of March 24, 2026, Utah has 486 confirmed cases of measles in residents as of 2025.[1][5] 107 cases have been reported in the last three weeks.[1] About half of Utah's cases occurred in the Southwest Utah Health District, with multiple unvaccinated communities.[3] In the 2024/2025 school year, about 10% of kindergarten children in Utah were exempt from the MMR vaccine or lacked vaccination records.[1] Currently, breakthrough cases (among those vaccinated) account for approximately 10.1% of confirmed cases, which corresponds to national trends.[1] Measles virus has been detected in wastewater in Salt Lake, Weber, and Morgan counties and the Southwest Utah Health District.[7]