Person infected with measles rode Amtrak train to D.C.

A passenger riding a train on Amtrak's Northeast Corridor has measles, according to a D.C. health officials.

The infected passenger rode Amtrak 175 southbound on March 19 and disembarked at Washington D.C.'s Union Station before seeking medical attention at an urgent care center.

The 175 originates in Boston. However, Massachusetts Department of Public Health officials said Wednesday afternoon that the passenger boarded the train in New York, not at South Station in Boston.

"Anyone who was exposed and is at risk of developing measles should watch for symptoms until 21 days following the date of their last exposure," the D.C. health department said in a statement. "If you notice the symptoms of measles, immediately isolate yourself by staying home and away from others. Contact your healthcare provider immediately."

Massachusetts health officials said they're working with counterparts in other jurisdictions and the U.S. Centers for Disease Control and Prevention to gather details about the situation.

Public health experts also recommend calling ahead to your doctor's office or emergency room to let them know you may have been exposed to measles, so they can take precautions to prevent exposing other patients.

While many people with measles experience high temperatures and the virus' signature red rash, advanced cases can lead to inflammation in the brain and death.

Measles is incredibly contagious. According to the CDC, "if one person has it, up to 9 out of 10 people nearby will become infected if they are not protected." The virus can survive for up to two hours in the air after an infected person has been there. And those infected are contagious before they ever exhibit signs of illness.

Fortunately, the measles vaccine has proven to be invaluable in reducing the number and severity of cases. Before the advent of the vaccine, measles were a perennial problem in the U.S., with hundreds of thousands of infections and up to 500 deaths per year. But those numbers collapsed following the adoption of the measles vaccine. By 2000, health officials were optimistic the illness had been eliminated in the U.S. Since then, there are have been small, but largely contained outbreaks in the country.

Nationwide, two people have died of measles this year, according to the CDC. And the recent measles outbreak in Texas and New Mexico is now over 370 reported cases — more than the total number of cases in all of the U.S. in 2024.

Records collected by the Massachusetts Department of Public Health show 96.3% of the state's kindergarteners had received a measles vaccine in the 2023-2024 school year. But the overall rate can mask lower numbers in some communities.

For measles, public health experts recommend a 95% vaccination rate to prevent the disease from spreading. A Metropolitan Area Planning Council map shows childhood vaccination rates have dropped below that in several dozen communities, but it doesn't specify which vaccines.

Adults vaccinated between 1963 and 1967 may need another dose of the current measles vaccine. The CDC suggests anyone who is not sure of their measles vaccination status check with their primary care provider.

With reporting from WBUR's Martha Bebinger