At Tully Medical Clinic Pharmacy in San Jose, more customers have been buying face masks — just to be cautious.

At Supertime Travel in San Francisco, Bay Area residents with trips booked to China are asking how they can change their plans.

And at UC Berkeley, officials have offered their students from China counseling and information about symptoms of novel coronavirus infection.

Though the Bay Area has no confirmed cases, concerns about the virus are spreading as schools, public officials and health officers work to tamp down rumors and provide up to date information.

“Businesses want information, schools want information, the general public wants information,” said Santa Clara County Public Health Department Health Officer Dr. Sara Cody on Wednesday.

A day earlier, her department ramped up its Emergency Operations Center — activated last Wednesday — and reassigned about two dozen staff to the center. Alameda and San Francisco counties have also activated operations centers.

“We’re on high alert because it’s a new virus so we’ve stood up this whole operation so we can learn as fast as we can, and handle a case and contacts when and if it should arise,” Cody said. “We have a lot of calls that are coming in.”

Some of those calls are from medical offices reporting possible coronavirus infections,  and the department is conducting tests to see if any of those people have the virus. Cody said the department would not reveal how many people are being tested, but would disclose information if a case is confirmed.

It’s likely just a matter of time before the virus hits the Bay Area, she said, “given the demographics of Santa Clara County and just the amount of travel we have to Asia and every other corner of the world.”

Anyone who in the past two weeks traveled to areas in China where the virus was circulating should be alert for symptoms, and “self-isolate” at home if they have fever, a cough or shortness of breath before calling their medical providers, Cody said.

In China, the number of confirmed infections hit nearly 6,000 Wednesday, with 132 deaths.  Five people were known to be infected in the U.S, which has reported no fatalities.

Health officials in Contra Costa County, San Mateo County and Alameda County also declined to say how many people have been tested to date. Last week, Alameda County’s public health department said it had tested fewer than 10 people at that point.

At UC Berkeley, spokesperson Janet Gilmore said this may be a particularly trying time for Chinese students. As of last fall, 2,763 undergraduate and graduate students at UC-Berkeley were from China, making it the top country of origin for international students.  Gilmore declined to say whether any students had been screened. Stanford University said in a statement that it is “actively monitoring” the situation but campus activities and functions continue as usual.

The University of California’s system-wide study abroad program has suspended its China programs, but there may be additional China programs administered by individual campuses, said Claire Doan, a spokeswoman for the UC President’s office.

Stanford Health Care said it wasn’t receiving calls from patients concerned about the virus, and is working closely with the U.S. Centers for Disease Control and county health office to “follow developments and align standard protocols,” according to spokeswoman Lisa Kim.

Local travel and tour agencies said they have seen an uptick in inquiries about the safety of traveling to China.

“We definitely got a lot of calls and questions on Monday, after Chinese New Year began,” said Gigi Young, manager of Supertime Travel in San Francisco’s Richmond district. She estimated they’re taking at least 10 calls a day from customers about whether they should cancel their travel plans to China.

“If you’re not leaving this week or next week, or not for a few months, we are telling people to hold of on canceling because they might not be able to get their fees back,” Young said. “But, if someone really feels the need to cancel, we will help them do that.”

The CDC has warned against all non-essential travel to China and Bay Area companies are taking heed. Apple CEO Tim Cook said the Cupertino firm was allowing only “business critical” travel to China for now. Apple has suppliers in Wuhan — where the outbreak started — and was working on plans to make up for any production loss. Potential effects on Apple’s business outside Wuhan were “less clear at this time,” Cook said on a conference call late Tuesday to discuss Apple’s fiscal first-quarter results.

Santa Clara chip maker Intel said it had restricted non-essential travel to China, in accordance with Centers for Disease Control recommendations. “We’re also working to ensure that our employees in China and elsewhere have the information and resources they need to stay safe,” Intel spokesman William Moss said Wednesday. Intel, which  has facilities in China, declined to discuss potential effects coronavirus might have on its business.

Google told tech website The Verge that it was temporarily closing all of its mainland China offices as well as offices in Hong Kong and Taiwan. The Mountain View digital advertising giant is advising employees currently in China to return home as soon as possible and to work from home for two weeks, the site reported. Other Bay Area tech companies that have either cancelled, or restricted business travel to China include HP and Facebook. Hewlett Packard Enterprise said it has banned business travel to Wuhan. Amazon and Microsoft also said they are barring employees from non-essential travel to China.

Tesla’s chief financial officer, on a conference call Wednesday, said China had ordered the Fremont-based electric car maker to shut down its Shanghai factory over coronavirus fears. “At this point we’re expecting a one to one-and-a-half week delay in the ramp of Shanghai-built Model 3s due to a government-required factory shutdown,” Zach Kirkhorn said, referring to production of the company’s lowest-priced car model.

School districts around the Bay Area have been contacting families, students and staff,  reassuring them that no coronavirus cases have been found in the region. In Fremont, at Mission San Jose High School, where 90 percent of the students enrolled are Asian, interim principal Jeff Evans said officials “have noticed more kids wearing masks at school.”

With rumors flying on Twitter and Facebook that coronavirus was in the Bay Area, a San Mateo County school district sought to dampen worries among parents and students. “These rumors have been investigated by both county and school district officials and they are not true,” Jefferson Union High School District superintendent Terry Deloria said in an announcement Tuesday.

Staff writers George Kelly and Joseph Geha contributed to this report