It's true that mandates could come in many forms. I was referring to constitutional challenges to government action such as the state law mandate at issue in Jacobson v. Massachusetts. States could of course (in theory) cook up any law they want, but these types of mandates tend to be "blanket" mandates that apply to everyone.
>>>Jacobson v. Massachusetts, 197 U.S. 11 (1905), was a
United States Supreme Court case in which the Court upheld the authority of states to enforce
compulsory vaccination laws. The Court's decision articulated the view that individual liberty is not absolute and is subject to the
police power of the state.<<<
en.wikipedia.org
Employer mandates are significantly different because the mandates typically say the employee has choice: "get vaccinated or find a job elsewhere." In theory it could implicate constitutional issues if the employer is the government or government funded, but these cases are largely just employment law issues. The recent hospital case in Texas is an example of this:
>>>There are two main exemptions to such an order. One is covered under the Americans with Disabilities Act. If an employee has a disability that would prevent or interfere with them getting the vaccine, they cannot be required to take the shot. The same is true for someone with a firmly held religious belief.<<<
Some former workers at Houston Methodist Hospital sued their former employer after refusing to get vaccinated. But their case probably won’t hold up.
www.texasstandard.org
That's not to say that every employer mandate will hold up in court. But, if one is struck down, the basis would most likely be that the employer mandate violated a law passed by a state government or the federal government (e.g. the ADA).