CHICAGO (WLS) -- Cook County is at high risk for an outbreak of measles, according to a new study led by a researcher at the University of Texas.
So far this year, Illinois has had seven measles cases. Researchers say one of the reasons Cook County is at risk is the number of international airline passengers traveling through Chicago.
"The majority of the new cases we are seeing are from international travelers, so that's the main reason the Chicagoland area, Cook County is on the radar," said Dr. Rachel Rubin, senior medical officer for the Cook County Dept. of Public Health.
According to the study, travelers coming from India, China, Mexico, Japan, Ukraine and the Philippines are the highest risk.
The CDC says the virus is so contagious, 90% of the people around an infected traveler could actually catch the virus as well - but only if they're not vaccinated. In an airport, that gives you an idea of how quickly it could spread.
"It doesn't mean you can't travel. It doesn't mean you can't go through O'Hare. It doesn't mean you are going to get exposed to measles. But it means make sure that you are protected and your children are protected with vaccination," Dr. Rubin said.
"You control if you're vaccinated, and that's the best you can do. Unfortunately, you can't control the other side. You just don't know what other person is coming with what," traveler Harshil Sheth said.
Cook County at high risk for measles outbreak, study says