Agencies
Services
News – Monday, May 5, 2025
2025 Measles Case Count Up to Six in Illinois
Risk to general public remains low, but unvaccinated and immunocompromised persons need to take precautions
Key Facts for Media:
Franklin-Williamson Bi-County area now meets the technical CDC definition of measles outbreak status with three linked cases.
There have been six Illinois adult measles cases in 2025 (with four in Southern Illinois and two in Cook County). No children have contracted measles in the state so far this year, and none of the adults has required hospitalization.
The risk of measles transmission for the general public in Illinois remains low. Vaccination is the most effective way of preventing measles.
SPRINGFIELD – The Illinois Department of Public Health (IDPH) has announced that the number of measles cases in Illinois so far in 2025 has reached six. Two new cases in Southern Illinois were confirmed over the weekend, adding to two in the Marion area that were identified in April. Two unrelated cases were previously confirmed in Cook County.
One of the new cases was confirmed over the weekend is in the Franklin-Williamson Bi-County area. This now meets the technical Center for Disease Control and Prevention (CDC) definition of an “outbreak” in that area (three or more cases that are linked to one another). Social links between the three cases are known.
Another Southern Illinois case may have visited locations in Missouri, including the St. Louis Aquarium. More information on that can be found at: Missouri DHSS announces possible measles exposure in St. Louis.
“The risk to the general public from measles remains low,” said IDPH Director Dr. Sameer Vohra. “The key to preventing measles is the highly effective MMR vaccine. Two doses are 97% effective in preventing this serious infection. I recommend that our Illinois residents make sure they and their family members are up to date on the MMR vaccine and all other age-appropriate immunizations.”
Current information on potential sites where infected individuals may have exposed others can be found on the IDPH website at Measles Exposure Locations. This will be updated as the Department gets more information.
IDPH continues to work with local health departments in the region, offering the latest public health guidance, laboratory testing services, and assistance with contact tracing and vaccination efforts as needed. IDPH has initiated mobile vaccination services in areas of Illinois with lower vaccination coverage rates to assist local health departments with their measles response and prevention efforts. For more information on measles prevention and treatment, and for regular updates on the evolving measles situation in the state including updated case counts, see the Measles page on the IDPH website.
