Chicago measles outbreak officially contained, vaccinations key to success

May 30, 2024

Six weeks without new cases marks end of outbreak, over 30,000 vaccinations administered

CDPH Public Information Office:

CHICAGO - The Chicago Department of Public Health (CDPH) is declaring the recent outbreak of measles in the City of Chicago officially over, with two full incubation periods for measles (42 days) having passed without any new cases.

On March 7, 2024, CDPH confirmed the first case of measles in Chicago in five years. As additional cases began to surface, including several in a new arrivals shelter, CDPH, in collaboration with many healthcare and community partners, mobilized a rapid response of symptom screenings for shelter residents, detailed contact tracing, and isolation of people with suspected or confirmed measles. In total, 64 individuals tested positive for measles, 57 of whom were associated with a shelter setting. Over 30,000 doses of measles-mumps-rubella (MMR) vaccine have been administered to Chicago residents. A CDPH report published by the Centers for Disease Control and Prevention (CDC) projected a high probability of an outbreak of over 100 cases without the City’s rapid intervention.

Special thanks are due to the Illinois Department of Public Health, Cook County Health, and the many community groups and healthcare partners who assisted in this response, and without whom the rapid vaccination of thousands of people and isolation of infected individuals would not have been possible. Although the outbreak in Chicago is over, measles remains on the rise domestically and around the globe. “The MMR vaccine is safe and by far the most effective way to protect yourself and others from future measles outbreaks, especially as tourism and travel ramp up over the summer months,” said CDPH Commissioner Dr. Olusimbo Ige. “Our goal is the elimination of measles in Chicago and everywhere, and with proper vaccination coverage, we know that zero is possible.”

For those who are traveling internationally, additional measles vaccinations may be recommended; talk with your healthcare provider before traveling about vaccinations you and your family may need. All Chicagoans are encouraged to review their immunization records or contact their healthcare provider to make sure they are up to date on the MMR vaccine per CDC recommendations. Immunization records recorded in the Illinois immunization registry can be accessed using the Illinois Department of Public Health Vax Verify portal.

A first dose of the MMR vaccine is recommended at 12 to 15 months of age and a second dose at 4 to 6 years of age, but it is never too late to get your MMR vaccine if you haven't already. Two doses of MMR vaccine are 97% effective against measles. CDPH offers MMR vaccinations at no cost for children eligible for the Vaccines For Children program at our various health clinics throughout Chicago. Adults who aren't sure if they're vaccinated against measles should contact their health care provider. For more information on measles please visit the CDPH website.