The City & County of San Francisco has released an official notice prohibiting employment discrimination because of COVID-19 status.
On March 7, 2021 a new protection ordinance prevents employers from discriminating against someone because of COVID-19 status.
Employers cannot try to fire or discipline an employee who needs to take time off work because they tested positive for COVID-19 or needs to quarantine because of COVID-19. This applies to job offers as well; employers cannot withdraw an offer to an applicant because they found out the person tested positive for COVID-19 or is quarantining due to exposure.
The ordinance is in effect until March 6, 2023.
You can read the official protections ordinance here from the government website and view the workplace poster.