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Health officials warn SF transit riders of possible measles exposure

Caltrain, Muni vehicles among places Bay Area residents might have come into contact with contagious party

The platform at SF Caltrain Station.
The Caltrain Station at Fourth and King is one of the places cited by the city as an area of potential measles exposure.
Photo by Sundry Photography

The San Francisco Department of Public Health (DPH) says that a patient infected with the measles was in SF at the beginning of April and may have exposed public transit riders to the highly infectious disease.

DPH spokesperson Rachael Kagan stressed in Tuesday’s emergency announcement that “there is no outbreak” and that “risk to the general public is very low,” but said that there is still some risk to anyone who may have been exposed.

The city provided a rough outline of the whereabouts of the infected party (an anonymous Santa Clara County patient) from April 1 through April 3.

Anyone who was in these areas—which include several Caltrain and Muni vehicles—at roughly the same time should be vigilant for potential symptoms:


Monday, April 1

  • 6:56 a.m.-8:13 a.m.: Caltrain train 319 northbound—first car
  • 8:45 a.m.-9:15 am: Caltrain train 232 southbound—last car
  • 8:15 a.m.-9:45 a.m.: SF Muni bus 47-Van Ness
  • 8 a.m.-10 a.m.: Hayes Valley Bakeworks, 525 Golden Gate Avenue
  • 8:30 a.m.-7 p.m.: Federal Building, 450 Golden Gate Avenue

Tuesday, April 2

  • 8 am-7:30 p.m.: Federal Building, 450 Golden Gate Avenue.
  • 8 a.m.-9:30 a.m.: Johnny Doughnuts, 392 Fulton
  • 8 a.m.-10 a.m.: Hayes Valley Bakeworks, 525 Golden Gate Avenue
  • 6:30 p.m.-8 p.m.: Double Decker Restaurant, 465 Grove

Wednesday, April 3

  • 8 a.m.-10 a.m.: Hayes Valley Bakeworks, 525 Golden Gate Avenue
  • 8:30 am-3:30 p.m.: Federal Building, 450 Golden Gate Ave
  • 3 p.m.-4:30 p.m.: Caltrain Station, 700 Fourth Street
  • 3:34 p.m.-5:10 p.m.: Caltrain train 258 southbound—second car from the back
  • 5:32 p.m.-6:15 p.m.: Caltrain train 279 northbound—second car from the front

Kagan also emphasizes that there is no risk of infection at any of these sites now.

[Update: DPH Director Dr. Julie Stoltey explains that these times represent “the window for possible exposure” at each of these sites.

“Measles is spread through the air from person to person, and the virus can stay in the air for up to an hour after an infected person was in the airspace,” Stoltey told Curbed SF via email. The timetable factors this extra time in for each locale, which is why many of them overlap.

Stoltey adds the although the patient lives in Santa Clara County, “There are no places in Santa Clara County that require notification of the public. “]

According to the Center For Disease Control, measles symptoms can develop anywhere from seven to 14 days after exposure. (DPH cited a seven to 21 day window.)

Common symptoms include fever, runny nose, cough, watery red eyes, and telltale white spots (“Koplik spots”) in the mouth.

The bright red rash commonly associated with the disease usually appears three to five days after early symptoms.

Measles virus. (Illustration)
Photo by Kateryna Kon

“Most people in San Francisco have been vaccinated,” says Dr. Tomas Aragon, Health Officer for the City and County of San Francisco.

However, the National Vaccine Information Center says that in up to two percent of cases vaccination fails, leaving the patient with no immunity.

Measles can also threaten those with compromised immune systems, children too young to have been vaccinated, and older people who never received the vaccine.

The World Health Organization (WHO) recorded roughly 110,000 measles deaths worldwide in 2017. Children under five are the most likely to suffer fatal complications from measles.

WHO describes measles as “one of the world’s most contagious diseases [...] spread by coughing and sneezing, close personal contact or direct contact with infected nasal or throat secretions.”

Anyone who develops measles symptoms should call their doctor immediately.