AUSTIN, Tx. (WJW/CNN/FOX) — Officials say at least five airports let people with measles go through security this month.

According to FOX, someone with measles traveled through two terminals at Chicago’s O’Hare International Airport in a two week span.

Other cities with similar cases included Richmond, Va., Austin, Tx., Los Angeles and Denver, ABC News reported.

“Measles is an acute, highly contagious viral disease. A small number of cases are capable of quickly producing epidemics,” said Dr. Mark Escott, Medical Director for Austin Public Health.

The best way to protect against measles is to get the measles vaccine, the report said. People who believe they may have been exposed to the disease should check their vaccination records and contact their health care provider, according to CNN.

The December exposures cap off the worst year for measles in more than two decades, with the Centers for Disease Control and Prevention reporting 1,276 cases, affecting the majority of U.S. states, ABC News reported. There were more cases of the infectious disease this year than there have been in the four years prior combined.