Wyoming Measles Cases Update

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Published December 18th, 2025

Detected March 17th, 2026

Summary

The Wyoming Department of Health reported five new measles cases in Fremont County, bringing the state's total for 2025 to fourteen. The cases are linked to out-of-state exposure and involve unvaccinated adults and children. The department is advising residents to ensure they are up-to-date on MMR vaccinations.

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What changed

The Wyoming Department of Health (WDH) has announced five new measles cases in Fremont County, increasing the state's total for 2025 to fourteen. These cases are part of a single transmission chain originating from out-of-state exposure and involve unvaccinated individuals, including both adults and children. While none required hospitalization, the WDH identified a potential public exposure at the Flying J Travel Center in Evanston on December 1, 2025. This notice serves to inform the public and reinforce vaccination recommendations.

Regulated entities, particularly healthcare providers and public health authorities, should be aware of the increased measles activity in Wyoming. The WDH strongly recommends that all residents ensure they and their children are up-to-date on the MMR vaccine. Healthcare providers should remain vigilant for measles symptoms and ensure proper reporting protocols are followed. Public health offices are providing vaccination services, and residents are encouraged to utilize these resources to prevent further spread of this highly contagious disease.

What to do next

Ensure all staff are aware of current measles activity in Wyoming.
Reinforce recommendations for MMR vaccination to patients and the public.
Maintain vigilance for measles symptoms and adhere to reporting protocols.

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Home » News » Five Measles Cases Identified in Fremont County, Bringing Wyoming’s Total to Fourteen

Five Measles Cases Identified in Fremont County, Bringing Wyoming’s Total to Fourteen

December 18, 2025

The Wyoming Department of Health (WDH) has identified five cases of measles among Fremont County residents. All five cases are part of the same chain of transmission, with the initial exposures to measles occurring outside the state and potential subsequent spread among close contacts. The five cases include both adults and children. All individuals were unvaccinated at the time of exposure. None were hospitalized. The total number of measles cases reported in Wyoming in 2025 is now fourteen.

Members of the public may have been exposed to measles at the following location and time. The measles virus can remain in the air for up to two hours after an infectious individual leaves an area.

Flying J Travel Center, 1920 Harrison Dr., Evanston, WY 82930 December 1, 2025, 2:30 PM through 5:00 PM

WDH did not identify any other Wyoming locations where the general public was exposed.

Measles is a highly contagious virus that can cause serious illness, including pneumonia, encephalitis, hospitalization, and death. The measles, mumps, and rubella (MMR) vaccine provides highly effective and long-lasting protection against measles infection. WDH recommends that all Wyoming residents ensure they and their children are up to date on MMR vaccines.

MMR vaccines are widely available in Wyoming through providers’ offices, pharmacies, and public health nursing offices. Residents of Fremont County can access MMR vaccinations at the public health offices in both Riverton and Lander. Visit the Fremont County Public Health website for locations, contact information, and hours of operation: https://www.fremontcountywy.org/government/departments/public_health/index.php

For more information on measles, including guidance on what to do if you were exposed, visit https://health.wyo.gov/publichealth/infectious-disease-epidemiology-unit/disease/measles/.