Parents across the country are opting their children out of vaccines for measles and other diseases at higher rates since the COVID-19 pandemic.
However, that is not the case across most of Illinois.
Nathan Lo is an infectious disease physician and a professor at Stanford University. He worked with other researchers to map the rise in religious and personal belief vaccine exemptions county by county.
“Outbreaks happen on a pretty spatially granular area, like it’s not the state, it’s not the country, it’s not even the county to some extent,” he explained. “It’s your local community. But county at least gets a lot closer to the scale that matters.”
Lo and the co-authors published their map of rising exemptions in January in the Journal of the American Medical Association.
Most Illinois counties have a non-medical exemption rate under one percent. Six counties in northern and southern Illinois have a two percent exemption rate.
The exemption rate is higher in most other states in the Midwest. In one Wisconsin county, between 10-20% of parents are opting their kids out of vaccines.
Despite the low rate of exemptions in Illinois, it does not have the highest rate of vaccination coverage.
Lo said that gap sometimes means a lack of access to vaccines, or even issues collecting good data.
“In a in a perfect world, you’d expect that vaccine coverage plus all your different exemptions all add up to 100% and exactly 100%,” he added. “That’s not necessarily the case.”
Lo said Illinois still has a relatively high vaccination rate and a measles outbreak is less likely in Illinois – or if it does happen, that it would stay in a small population.
He gave the example of an outbreak in Chicago in 2024 among people staying in a temporary migrant shelter. Most had not been vaccinated beforehand.
Lo advised parents to talk with their child’s doctor about staying up to date on their vaccines. Measles, for example, can land kids in the hospital and lead to complications like lung failure years later. He said the measles shot is safe and one of the best vaccines available.