The Illinois Department of Public Health (IDPH) has declared the end of the largest measles outbreak in Illinois since 1990. With no new cases reported for over 42 days, the outbreak, which began on March 7 and resulted in 67 reported cases, has been contained. The majority of cases were linked to a Chicago shelter for new arrivals, with subsequent cases reported in suburban Cook County, DuPage, Lake, and Will counties.
Cooperation among state and local health departments, including IDPH, the Illinois Department of Human Services (DHS), and the Illinois Emergency Management Agency (IEMA), was crucial in managing the outbreak. Efforts included activating Emerging Diseases funding to support a DHS-run quarantine hotel-shelter in Chicago, which helped quarantine vulnerable populations. Additionally, IDPH expanded laboratory capacity for expedited measles testing and coordinated educational sessions to promote vaccination and awareness.
The state facilitated contact tracing, reorganized mass events to minimize the risk of super-spreader events, and provided on-site clinical support and infection control assessments at shelters and quarantine sites. The IDPH vaccine team also augmented the vaccine supply and developed a school vaccine dashboard to guide local vaccination efforts, ensuring new arrivals attending schools were quickly vaccinated.
IDPH emphasizes the importance of vaccinations, noting that one dose of the MMR vaccine is 93% effective against measles, and two doses are 97% effective. Vaccination rates have declined since the COVID-19 pandemic, increasing the risk of vaccine-preventable diseases. Individuals are encouraged to ensure their families are up to date on all recommended vaccines to protect themselves and their communities. For more information, contact your primary care provider or visit the IDPH website.
