On Mar. 25, 2025, the Oklahoma State Department of Health (OSDH) reported that nine additional measles cases had been identified among unvaccinated individuals in northeastern Oklahoma.

Two of the previously reported probable cases were updated to confirmed cases due to linkage with a close contact that had confirmatory measles testing. Investigations for the five new cases found no additional public setting exposures.

All cases were linked through exposures to household or extended family; and initial cases reported exposure to the measles outbreak in West Texas and New Mexico. At this time, no cases resulted from exposure to public settings.

Public exposures were limited due to most of these individuals recognizing their exposure and excluding themselves from public settings.

The Oklahoma State Department of Health (OSDH) worked collaboratively with the Cherokee Nation, health care community and the Tulsa Health Department (THD) to complete the necessary steps when these measles cases were identified in northeastern Oklahoma.

When a measles case is identified, it is essential for an individual to share any requested information when contacted by the health department. This step is crucial for conducting a timely public health investigation and prompt public notification to protect the health of Oklahomans.

Individuals should be aware of measles activity occurring in Oklahoma and neighboring states. Measles can be prevented with an MMR vaccine. Two doses of the MMR vaccine are expected to be 97% effective at preventing measles, while one dose is about 93% effective.