Here is a quote from an actual lawyer (Ryan Watkins, Partner @ Whitten & Lublin Employment Lawyers):
“The exception is where an employee has a credible human rights claim, says Watkins. An employee may object to taking the vaccine on religious grounds, or because they have an allergy or other medical condition. While the employer has the right to ask questions and verify the claim, a bona fide human-rights issue will trump the employer’s interest in protecting the health and safety of the workplace through mandatory vaccination, says Watkins.“