The California Senate passed a bill requiring all healthcare workers to either be vaccinated against influenza or wear a mask (PDF) in patient-care areas during flu season.

The bill, which would go into effect Jan. 1, 2015, is supported by a number of state healthcare organizations, including the California Hospital Association and the California Medical Association. The bill is opposed by a number of labor groups, including the California Nurses Association.

“We know that higher vaccination levels among staff have been associated with a lower risk of hospital-acquired influenza cases, Dr. James Hay, president of the CMA, said in a release. “SB 1318 will help to keep the numbers of hospital-acquired flu fatalities low.”

The bill now moves to the state's other house, the Assembly, for consideration.