Officials warn measles patients passed through 5 major U.S. airports this month

Travelers with confirmed cases of measles passed through five U.S. airports this month and exposed an unknown number of passengers to the disease, ABC News reports, citing city health officials.

Why it matters: The Centers for Disease Control and Prevention says measles, a highly contagious virus that can spread from an infected person through coughing and sneezing, can live for up to two hours in an airspace where the the person coughed or sneezed.

Affected airports and cities

Chicago: An individual with measles traveled through two terminals at O'Hare International Airport over the course of a week. The person passed through O'Hare's Terminal 1 on Dec. 17 and through Terminal 3 on Dec. 12, according to the Chicago Department of Public Health.

Richmond, Virginia: A person with measles visited Richmond International Airport on Dec. 17, according to the Virginia Department of Health.

Austin, Texas: An individual with a diagnosed case of measles visited the United Airlines gate area at Austin-Bergstrom International Airport on Dec. 17, Austin Public Health reports.

Denver and Los Angeles: Three unvaccinated children traveled to a country with an ongoing measles outbreak in early December and tested positive for measles when they returned.

• The children visited parts of Denver International Airport on Dec. 11, including Concourse A, the baggage area and the pickup area, Colorado's Tri-County Health Department reported.
• The children also traveled through Terminals 4 and 5 at Los Angeles International Airport on Dec. 11, according to the Los Angeles Department of Public Health.

What they're saying: "A small number of [measles] cases are capable of quickly producing epidemics," Dr. Mark Escott, medical director for Austin Public Health, said in a statement.

The big picture: 2019 has been the worst year for measles cases in more than two decades. The CDC has so far confirmed 1,276 cases in most U.S. states.

• Globally, the United Nations has so far confirmed 440,263 cases this year, up from around 350,000 cases in 2018, Axios' Marisa Fernandez reports.

Go deeper:

• Over 140,000, mostly children, died from measles in 2018
• Germany makes measles vaccine mandatory
• Measles can give your immune system amnesia