Illinois health director praises coordinated effort to stop measles outbreak

The Illinois Department of Public Health has declared this spring’s measles outbreak officially ended, and is promoting action to prevent the continued spread of the virus.

A total of 10 measles cases were detected in Illinois in April and May, according to the IDPH.

Eight of the cases were located in southern Illinois and were linked to one another. The additional two were unrelated cases identified in Cook County, which did not spread and did not constitute and outbreak by definition.

The state officially declared the outbreak over this week as more than 42 days – two full incubation cycles for the virus – have passed since the last confirmed case was discovered on May 22.

“The end of this outbreak, capping at just 8 cases and no serious illnesses in Illinois, is a testament to the deliberate, decisive, and successful work of our public health and medical professionals,” IDPH Director Dr. Sameer Vohra said in a released statement.

The department credited Illinois’ limited outbreak with a fast, coordinated reaction by local health departments to identify exposed individuals and encourage quarantines and monitoring.

Local health departments also increased preventative vaccination efforts including deploying mobile vaccination units, expanded testing capacity, and working to provide information to people in impacted areas, according to the IDPH.

The state estimated that 2.5 million people were reached through these preventative measures this spring.

Cases on the rise nationally

The Illinois measles cases were part of a larger nationwide increase of the disease which was officially declared eradicated in the U.S. in 2000.

According to the IDPH, this year has seen the largest number of measles cases nationwide in 33 years, with the Centers for Disease Control and Prevention documenting 1,288 cases this year across 39 jurisdictions. Of those cases, three have been fatal, the same number of fatal measles cases that occurred between 2001 and 2024.

The outbreak has come amid a growing amount of vaccine skepticism nationwide following the COVID-19 pandemic. According to Gallup, only 69% of Americans said they believed childhood vaccines were “extremely” or “very” important in 2024, as opposed to 94% in 2001.

IDPH reports that 92% of cases diagnosed this year have affected unvaccinated individuals or individuals whose vaccination status is unknown.

“Vaccination remains our most effective tool to prevent measles,” Vorha said. “I recommend that Illinois residents make sure that they and their family members are up to date on the measles/mumps/rubella vaccine and all other age-appropriate immunizations.”

The IDPH announcement shared CDC statistics noting that one dose of the measles/mumps/rubella (MMR) vaccine is 93% effective against measles and two doses is 97% effective against the virus, making vaccination “a significant contributing factor in containing or preventing outbreaks.”

The department emphasized in its statement that “there has been no link established between autism and the MMR vaccine through multiple scientific studies both in the U.S. and other countries,” directly contradicting vaccine-skeptical misinformation which has been spread online and by current Health and Human Services Secretary Robert F. Kennedy Jr.

Who can get measles

Measles can be spread through the air when an infected person coughs or sneezes. Common symptoms include coughing, runny nose, red irritated eyes, and a rash across the skin, however, it can also cause serious and long-term complications, including pneumonia and encephalitis, according to the IDPH.

Measles is particularly dangerous to young children. The IDPH stated that about one in five children under the age of 5 end up hospitalized after contracting measles.