To protect patients, more than 100,000 health care workers in hospitals, nursing homes, clinics and ambulances are required to be vaccinated against the flu or wear a surgical mask. But in hospital settings alone, roughly 9 percent declined the vaccine during the flu season that ended March 31, according to an inewsource survey. San Diego County health officials issued that order last November as some local hospitals were reporting as many as 33 percent of workers declined to get vaccinated during the 2013-2014 season. Workers, including physicians, who receive flu shots or nasal mist are identified with a nonremovable sticker on their badges. Workers without a sticker are supposed to be masked when in patient care areas.