BART measles alert: LinkedIn worker rode in rush hour

Commuters wait for trains in the Montgomery BART Station in January 2013. Commuters wait for trains in the Montgomery BART Station in January 2013. Photo: Pete Kiehart / The Chronicle Photo: Pete Kiehart / The Chronicle Image 1 of / 1 Caption Close BART measles alert: LinkedIn worker rode in rush hour 1 / 1 Back to Gallery

Health officials issued a sweeping alert to BART riders Wednesday after a LinkedIn employee with measles commuted in and out of San Francisco last week and potentially exposed thousands of people to the virus.

The risk to individuals is slim because most people in the U.S. are vaccinated, and the vaccine is 95 to 99 percent effective, public health experts said. Officials nonetheless urged anyone who believes they have symptoms to contact a doctor immediately.

The person, an unnamed Contra Costa County resident, rode BART to and from the LinkedIn offices in San Francisco on Feb. 4-6. BART will not attempt to contact everyone who may have been on trains those days, but health officials are trying to reach anyone they know had direct contact with the sick person.

The passenger, who is an employee at the professional social networking site, was confirmed this week as the first measles case in Contra Costa since the start of an outbreak tied to a December guest at the Disney theme parks in Southern California. How the Contra Costa resident contracted measles is not yet known.

LinkedIn officials said they were notified Tuesday that one of their workers was sick with measles, and the company sent a message to all employees that day, advising them about possible exposure.

The person reported traveling between the Lafayette BART Station and the Montgomery Street Station in downtown San Francisco from about 6 to 8 a.m. and from 7 to 9 p.m. last week. BART officials estimated that as many as 25,000 people rode trains on the Pittsburg-Bay Point route during each of those periods.

“We think the general risk is going to be low,” said San Francisco Health Officer Tomas Aragon at a news briefing Wednesday.

Health officials at the briefing noted that people vaccinated against measles should not be concerned, “but there’s always people who didn’t get vaccinated for a variety of reasons,” Aragon said.

More than 100 people have been reported sick with measles since the statewide outbreak began in December, according to the California Department of Public Health. There have been 15 cases in five Bay Area counties: Alameda, Contra Costa, Marin, San Mateo and Santa Clara.

'Contact tracing’

The Contra Costa patient’s health care provider reported the new measles case to public health authorities, who then began the arduous task of “contact tracing,” or talking to people who knew the person with measles and may have been exposed. In Alameda County last month public health officials interviewed more than 500 people associated with six cases there.

“We’re trying to figure out who that person is in contact with,” said Erika Jenssen, who heads the communicable disease program in Contra Costa. “With measles it’s a little more difficult” than with other infectious diseases because the virus is so contagious, she said.

Health officials said the virus can stay in the air for up to two hours, and that this case was of particular concern because of the potential exposure to thousands of BART passengers.

The passenger also visited the E&O Kitchen and Bar at 314 Sutter St. in San Francisco on Feb. 4. Health officials said patrons who were at the restaurant from 5:30 to 7 p.m. that day may have been exposed.

Akop Paronyan, general manager at E&O, said Wednesday that all employees who worked at the restaurant during that time were fully vaccinated and no one has reported symptoms. He said he asked health officials about taking such precautions as closing down the restaurant but was told that wasn’t necessary.

“I will say I called my mom to make sure I’m immunized. And she found the records,” Paronyan said. “But the department of health was pretty helpful in setting our mind at ease.”

Measles is caused by a highly contagious virus that, spread through coughs and sneezes, can remain airborne and capable of infecting people for hours. Most people who fall ill will experience mild symptoms for a week or two, but about 20 percent of people can develop pneumonia, and 1 or 2 in 1,000 can develop encephalitis or die.

Rash lasts 5 to 6 days

Symptoms usually start one to three weeks after exposure, and may include high fever, runny nose, coughing and watery, red eyes. The characteristic rash develops two to four days after the fever, usually starting on the forehead and moving down the face and neck to the rest of the body. The rash usually lasts five or six days.

An infected person is contagious for several days before and after the rash appears. Because the early symptoms can be easily confused with influenza or other common illnesses, people may not know they’re exposing others to measles.

Measles has been considered eliminated in the United States since 2000. Before the vaccine was developed in the 1960s, California would see up to 40,000 cases a year.

That number has dropped steadily since then. In the past two decades, with more than 90 percent of children vaccinated, cases have ranged from a low of four in 2005 to 60 in a year with a large outbreak. As of Monday, there had been more than 100 confirmed cases of measles in California since December, 15 of them in the Bay Area.

Jenssen with Contra Costa County said the measles outbreak “highlights the need for people to be vaccinated, and this is just another example of how interconnected our region is and how important it is for everyone to be up to date on their immunizations.”

This is the second time in a year that BART riders have been warned about possible measles exposure. In February 2014, a Contra Costa resident sick with measles took BART to commute to classes at UC Berkeley, prompting an aggressive public health campaign to reach the tens of thousands of people who may have been exposed.

Health officials believe the student, who had not been vaccinated, contracted measles during a trip to the Philippines.

“There were no follow-up people infected,” said BART spokeswoman Alicia Trost. “That’s a little comforting to know.”

Kurtis Alexander and Erin Allday are San Francisco Chronicle staff writers. E-mail: kalexander@sfchronicle.com, eallday@sfchronicle.com Twitter: @kurtisalexander, @erinallday