Health officials are warning travelers who made their way through Newark Liberty International Airport earlier this month that they may have been exposed to measles.
The passenger in question landed in Terminal 5 (the worldwide terminal) then transferred to a domestic flight in Terminal 1.
But officials say anyone who was in the airport between 6:30 a.m. and 1 p.m. on Wednesday may have been exposed to the disease.
The Centers for Disease Control and Prevention has contacted the people who sat next to the infected passenger on the flight.
The traveler landed at Chicago O'Hare and was in multiple terminals of the airport before boarding a second flight from Chicago to Little Rock, AR, WTVG reports. If infected, symptoms could develop as late as January 23.
"Measles is a very contagious virus, and it can hang around in the air for up to an hour or two after a person has left", said Dr. Allison Bartlett with University of Chicago Medicine.
"Getting vaccinated not only protects you, it protects others around you who are too young to get the vaccine or can't receive it for medical reasons".
Measles symptoms include rash, high fever, cough, runny nose and red, watery eyes.
In the statement, the agency said anyone else concerned about possible measles infection should "call a health care provider before going to a medical office or emergency department". The disease is most easily spread through coughing and sneezing and can cause further complications such as pneumonia or encephalitis.
If you have the MMR vaccine, you should be protected. The Department of Public Health has asked anyone who was at the airport during that time to get checked.