Idaho has the lowest measles vaccination rate among kindergartners in the United States for the 2024-2025 school year, with only 78.5% of children receiving the required immunization.

The vaccination rate falls well below the threshold recommended by public health officials to maintain community immunity against measles, a highly contagious viral disease that can cause serious complications including pneumonia, brain swelling, and death.

Measles requires vaccination rates of approximately 95% in a community to prevent outbreaks through herd immunity. The current rate in Idaho leaves a significant portion of the kindergarten population vulnerable to infection.

Public health experts have expressed concern about the potential for measles transmission, particularly given the disease's ability to spread rapidly in unvaccinated populations. The virus can remain airborne for up to two hours after an infected person leaves a room.

The low vaccination rate in Idaho reflects broader trends in some regions where vaccine hesitancy has increased in recent years. State health departments typically track kindergarten vaccination rates as an indicator of community immunization coverage.