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A Facebook contractor based in Seattle tested positive for coronavirus, the company confirmed Wednesday.

The person was last in the Stadium East office on Feb. 21. Facebook closed its Stadium West and Stadium East offices, located in Seattle’s Sodo neighborhood, until March 9.

“We’ve notified our employees and are following the advice of public health officials to prioritize everyone’s health and safety,” a Facebook spokesperson said in a statement.

The company is encouraging all Seattle-area employees to work from home until March 31. Facebook employs more than 5,000 Seattle-area people across nearly 20 offices.

This incident is separate from the Amazon employee who tested positive for COVID-19 and had dinner at Facebook’s Arbor Blocks office in Seattle on Feb. 24.

Seattle has become a U.S. epicenter of the coronavirus. King County public health officials reported 10 new confirmed cases of COVID-19 today, including one additional death. That brings the total for King County to 31 confirmed cases, with nine deaths.

Officials advised people to work from home and postpone gatherings to slow the spread of the infection.

Follow this post for ongoing updates on the novel coronavirus outbreak.