Yes, your boss can fire you if you refuse to get a Covid vaccine

 Under Title VII of the Civil Rights Act of 1964, if taking the vaccine is a violation of a “sincerely held” religious belief, they, too, would potentially be able to opt out.

https://www.cnbc.com/2020/12/07/covid-vaccine-update-your-boss-can-fire-you-if-you-refuse-the-coronavirus-shot.html