Idaho’s kindergarten class has slipped to a measles vaccination rate of 78.5% for the 2024‑2025 school year, far below the 95% herd‑immunity target. The shortfall caps the state’s maximum possible coverage at roughly 85%, according to health officials. With exemptions rising, the gap leaves thousands of children vulnerable to an outbreak and puts schools at risk of temporary closures.

Since January 2026 Idaho has reported nine measles cases across three counties, all linked to unvaccinated or unknown‑status individuals. An earlier cluster in August involved two northern counties with no clear epidemiological connection, prompting epidemiologist Christine Hahn to warn that undetected spread could be simmering. Nurses are reaching out in the districts.

Health officials are urging parents to complete the two‑dose MMR vaccine schedule, which offers 97% protection and lifelong immunity. The recommendation targets children 12–15 months for the first dose and 4–6 years for the booster. With Idaho lagging behind every other state, the push aims to close the immunity gap before any larger outbreak takes hold. Schools can verify records through the state portal.