As measles outbreaks worsen nationwide, Chicago doctors are urging people to stay current on their vaccinations against the highly contagious virus.
Measles, a disease once considered eradicated from the United States, periodically pops up in small numbers in Illinois and throughout the nation. But the latest outbreak that began in West Texas is one of the worst in recent memory, infectious disease and pediatric doctors told the Sun-Times.
“This is much more widespread and much more serious,” said Dr. Tina Tan, a pediatrician specializing in infectious disease at Lurie Children’s Hospital.
At least 164 cases have been confirmed nationwide and an unvaccinated child has died from the virus in West Texas, the first confirmed measles death in the U.S. in 10 years, according to the Centers for Disease Control and Prevention.
And although no cases have been reported in Illinois so far this year, the cases in Texas and other states are a reminder for people to stay vigilant, Tan said.
“What people need to recognize is measles can be a serious disease,” she said. “And the vaccine for measles is the most important and effective preventative measure for protecting their child against measles.”
The current two-dose measles vaccine, which includes a live virus, has been around since 1968, said Dr. Anu Hazra, an infectious disease doctor with UChicago Medicine.
The first dose is given when a child is between 12 and 15 months old. The second dose is given between the ages 4 and 7. That first dose alone gives 93% immunity and two doses supplies 97%, Hazra said.
“We can all take a deep breath. If you got both doses, you are protected,” Hazra said. “The measles vaccine we’ve had since the late 1960s is really potent, and it’s really something we don’t think about boosting in any situation.”
During the early to mid 1960s, a weaker version of the vaccine without a live virus was available. And people born before 1957 gained immunity because they were most likely exposed to measles during their childhood, Hazra said.
For people born between 1957 and 1968, Hazra encouraged them to consider getting inoculated with the current vaccine, also called MMR because it covers measles, mumps and rubella. And for people unsure about whether they received the vaccine as a child, they should talk with their health care provider and get vaccinated, Hazra said.
“Especially if you’re concerned about being exposed, it would be good to get the current live vaccine,” he said. “And after two doses, you’re protected for life.”
Herd immunity for measles is reached when 95% of the public is vaccinated, Hazra said, which protects the people who can’t get the live virus vaccine, such as babies under 12 months and people who are severely immunocompromised.
For the 2023-24 school year, the vaccine rate for Illinois school-aged children was 94.4%, according to data from the Illinois Department of Public Health. Chicago’s was at 92.2%.
“To get this under control, we need to get our vaccine numbers up,” said Tan, who also serves as the president of the Infectious Diseases Society of America. “Getting vaccinated protects yourself and your family and it means you’re looking out for others around you in the community.”
Outbreaks have been reported in other states besides Texas, including in New Mexico, Alaska, California, Georgia, Kentucky, New Jersey, New York City and Rhode Island, the CDC reports.
So far this year, no measles cases have been reported in Illinois, according to state health figures. In 2024, there were 67 cases, by far the most cases in the last 15 years. The majority of those cases —61 — were reported in Cook County, and several of those cases were likely connected to measles outbreaks at migrant shelters in Chicago.
Measles can cause serious complications and kill people, Tan said. The more common complications include ear infections, diarrhea hearing loss, blindness, pneumonia and severe brain inflammation that can lead to convulsions, deafness or intellectual disabilities.