The city of San Francisco announced on Wednesday that it would require all municipal employees to be vaccinated against COVID-19 or they could face penalties or risk losing their jobs.

The new rule will not take effect until the vaccines have received full approval from the US Food and Drug Administration, which has so far green-lit their use on an emergency basis due to the pandemic

San Francisco will then require all 35,000 of its employees, including police and firefighters, to be vaccinated. Those who fail to comply and do not receive an exemption for medical or religious reasons will be punished or could even be fired.  “It’s really a decision for the health and safety of our employees and our public that we serve,” said Carol Isen, the city’s director of human resources.

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“It’s about protecting the city as an employer from what we deem to be an unacceptable risk.”

The local branch of the Service Employees International Union, which represents around 20,000 city employees, called the move a “threatening mandate” and said such a requirement must be negotiated and not imposed.

More than 150 employees at one of Texas’s largest hospitals were fired or resigned this week after refusing to comply with a COVID vaccination requirement. Officials at Houston Methodist had told its staff they needed to have received a COVID vaccination by June 7.

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Some staff members had filed a lawsuit against the hospital, accusing it of “forcing its employees to be human ‘guinea pigs’ as a condition for continued employment.” The lawsuit was dismissed by a judge who said the vaccines’ safety was not at issue.

The city of San Francisco, which adopted measures early on in the US coronavirus outbreak to stop its spread, has one of the highest vaccination rates in California, about 80% of residents 12 and over have received at least one dose.