Santa Clara County Board of Supervisors President Cindy Chavez gets her flu shot at the Santa Clara County Fairgrounds. (Jana Kadah/BCN Foundation)

County health care workers will be required to get a flu shot by the end of November under an order issued Wednesday by the county’s top health official.

The order, which takes effect Nov. 1, will require workers to get the annual flu vaccine or, if granted a medical or religious exemption, wear a surgical mask or respirator any time they are indoors.

Workers in health and congregate care facilities will be subject to the order, including nurses, physicians, technicians, therapists and pharmacists at hospitals, skilled nursing facilities, dental offices and other similar care facilities and clinics.

The order will remain in effect until May 31, 2023, unless extended by county Health Officer Dr. Sundari Mase, who argued the requirement will help prevent flu transmission as the virus circulates alongside COVID-19.

“The flu and COVID-19 will likely be spreading at the same time, and relaxed COVID-19 mitigation measures may result in an increase in flu activity during the upcoming season,” Mase said. “Influenza is preventable with a vaccine that is currently available.”

Mase also encouraged all county residents not affected by the order to get a flu vaccine, especially first responders.

Flu season generally lasts through the end of May, with transmission of the virus spurred by large groups of people gathering indoors during the winter.

Flu vaccines are available at primary health care providers, retail pharmacies and some COVID-19 vaccination clinics.