Three people with measles passed through Los Angeles International Airport last week, Los Angeles County Health officials said Monday – and it’s unclear how many people were exposed to one of the most contagious viruses in the world.

The infected people, who were not Los Angeles County residents, were at the airport and could have exposed other travelers on Wednesday in Terminals 4 and 5 between 6:50 a.m. and noon. The Department of Health said there is “no known current risk” related to measles in those terminals, but it was trying to identify others who would have been exposed if they encountered the infected travelers.

The Department of Health said anyone who was in those terminals in that span should review their immunization records and look for signs of illness. Those without a vaccine risk developing measles for up to 21 days after exposure.

“For those who are not protected, measles is a highly contagious and potentially severe disease that initially causes fever, cough, red, watery eyes, and, finally, a rash,” said Muntu Davis, a Los Angeles County health officer. “Measles is spread by air and by direct contact even before you know have it.”

On average, more than 174,000 people travel through Los Angeles International, or LAX, each day on 1,659 flights. According to its website, LAX is the third busiest airport in the world.

Twenty Los Angeles County residents have contracted measles in 2019, according to the Department of Health, and 14 cases involving non-residents traveled through Los Angeles County this year. The majority of the patients in these cases were unvaccinated or did not know their immunization status.


In April, hundreds of students and staff members at two Los Angeles universities were quarantined because of potential measles exposure at a campus library. More than 500 students and 100 staff members who could not verify their vaccination were instructed to stay home and avoid contact with others.

Davis emphasized the importance of the measles vaccine in preventing the disease from spreading.

A recent study suggests that a measles infection wreaks havoc on the immune system, destroying up to half the existing antibodies the human body needs to protect against other viruses and bacteria. In August, the World Health Organization said there were more reported cases of the virus in the first half of 2019 than any year since 2006.

In August, an Israeli flight attendant died after contracting measles months prior and falling into a coma. The 43-year-old flight attendant for the national airline El Al had flown back to Israel in March from John F. Kennedy International airport in New York.

The Washington Post previously reported that the woman had been vaccinated as a child. However, that woman, born in the 1970s, likely received a single dose of the vaccine. Israel now recommends that children receive one dose as an infant and another during first grade.

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The Washington Post’s Lena H. Sun and Morgan Krakow contributed to this report.