April 24, 2025
Illinois health authorities have officially declared the end of the states most significant measles outbreak since 1990. The Illinois Department of Public Health IDPH confirmed that no new cases have been reported for over 42 days, marking two full incubation periods for the virus. The outbreak, which began on March 7, 2024, resulted in 67 confirmed cases, predominantly linked to a migrant shelter in Chicago. citeturn0search1
Outbreak Overview
The initial case was identified in a oneyearold child residing in a temporary shelter for migrants in Chicago. Due to the high transmissibility of measles and low vaccination coverage among shelter residents, the virus spread rapidly within the facility. In total, 64 individuals in Chicago tested positive, with 57 cases associated with shelter settings. citeturn0search5
The outbreak extended beyond Chicago to suburban Cook County, DuPage, Lake, and Will counties. However, swift public health interventions, including mass vaccinations, symptom screenings, contact tracing, and isolation of infected individuals, effectively contained the spread in these areas. citeturn0search1
Public Health Response
In response to the outbreak, over 30,000 doses of the measlesmumpsrubella MMR vaccine were administered to Chicago residents. The Chicago Department of Public Health CDPH, in collaboration with state and local partners, mobilized resources to support affected communities. This included establishing quarantine facilities for vulnerable populations and expanding laboratory capacity to expedite measles testing. citeturn0search0turn0search1
Dr. Sameer Vohra, IDPH Director, praised the coordinated efforts: Public health is a team sport founded on partnership, and this was no better exemplified than during this recent outbreak. citeturn0search1
Lessons and Ongoing Vigilance
The outbreak underscored the importance of maintaining high vaccination coverage, particularly in congregate settings. While the outbreak has been declared over, health officials emphasize the need for continued vigilance. The CDPH advises all residents to review their immunization records and ensure they are up to date on the MMR vaccine. citeturn0search10
Dr. Olusimbo Ige, CDPH Commissioner, stated, The MMR vaccine is safe and by far the most effective way to protect yourself and others from future measles outbreaks. citeturn0search0
As measles remains a global concern, public health officials continue to monitor for potential cases and encourage vaccination to prevent future outbreaks.
For more information on measles and vaccination services, residents can visit the CDPH website or contact their healthcare provider.