Art Saludares got nabbed shortly after he walked down a hallway after lunch in the hospital cafeteria.
"Was that you I saw walking without a mask?" asked a good-natured, but serious, email from Suzanne Cistulli, director of infection prevention and control at San Jose's O'Connor Hospital.
Many Bay Area hospitals are vigorously enforcing a new mandate that health care workers throughout Alameda, Contra Costa and Santa Clara counties get a flu shot or don a mask during the flu season.
Comprehensive numbers are not yet available, but some institutions are reporting dramatic increases in employee vaccination rates.
Many hospitals have set up flu stations with employee masks at entrances to buildings and are using stickers on employee badges to identify those who have had a shot. Stations with sanitizers and masks have also been set up for patients.
The goal of the mandate is to protect patients who are most at risk, including infants, the elderly and those with weakened immune systems.
Local health officers issued the mandate after an analysis by this newspaper revealed that nearly one-third of employees at many Bay Area hospitals failed to get a flu shot during the 2010-11 season, and at some institutions, half of workers were unprotected.
At O'Connor Hospital, 76 percent of employees were vaccinated last year. This season, the number jumped to 95 percent.
Sutter Delta Medical Center in Antioch also has reached a 95 percent vaccination rate, up from 67 percent two years ago.
And Alta Bates Summit Medical Center facilities in Oakland and Berkeley have an 85 percent employee vaccination rate, compared with 54 percent two years ago.
"My sense is that it's working very well," said Dr. Marty Fenstersheib, health officer for Santa Clara County. "I'm happy that it's in place, given all that's going on with the flu."
It is up to each institution to enforce the policy, which also applies to nursing homes, adult day health centers, ambulance companies and other health facilities.
Stanford Hospital has had its own policy in place for four years. Its medical staffers who do not have a medical or religious exemption must get a flu shot or are subject to suspension of their hospital privileges.
Saludares, who supervises sterile processing of surgical instruments at O'Connor, supports the county mandate even though he must wear a mask. He declined to have a vaccination because of a severe reaction to a shot two years ago.
"At first, people politely accused me of, 'Why didn't you take the flu shot?'" he said. "We have a culture here of strict compliance with infection control. I like to be a part of the solution. We have strong flu this year and I have no problem with the mandate."
Others do have a problem with it, however.
Kristina Suzuki, a registered nurse at O'Connor, always declines a flu shot. "I feel it should be a personal choice," she said. "I didn't like being told I had to do it. I feel that through good hand washing and covering your cough, you can protect yourself."
She has been wearing a mask since October and found it warm and obtrusive at first, but she's getting used to it.
Suzuki wore a mask last week when caring for San Jose resident Rosemary Farris, who was in the intermediate care telemetry unit with pneumonia and heart problems.
Farris was unaware of the policy and assumed Suzuki wore the mask to protect herself from Farris' pneumonia. But when she learned of the mandate, Farris said she is "all for it," especially because this could be an especially severe flu season.
The California Nurses Association encourages its members to get shots but objects to the mask requirement. "Surgical masks are very flimsy and they're not very effective," said Malinda Markowitz, a CNA co-president.
Markowitz argues that hospitals, which have cut back on housekeeping staff, would do better to focus more on regularly cleaning railings, door handles and the computers and medication carts that nurses use.
The flu shot and masks may not be perfect, but they are one of the best ways to protect the public, said Dr. Bill Walker, health officer for Contra Costa County.
"We're hearing that having that (mandate) in place has helped a lot," he said. "Anecdotally, I'm hearing that compliance has remarkably increased."
Sandy Kleffman covers health. Contact her at 510-293-2478. Follow her at Twitter.com/skleffman.
Immunization rates jumped dramatically at some hospitals after health leaders in Santa Clara, Alameda and Contra Costa counties mandated that health care workers get a flu shot or wear a mask during the flu season.
At O'Connor Hospital in San Jose, 76 percent of employees were vaccinated last year. This season, the number jumped to 95 percent.
Sutter Delta Medical Center in Antioch reached a 95 percent vaccination rate, up from 67 percent two years ago.
Alta Bates Summit Medical Center facilities in Oakland and Berkeley have an 85 percent employee vaccination rate, compared with 54 percent two years ago.