The federal government should protect the constitutional rights of its citizens. Citizens should be free to do whatever they want until they infringe on the rights of others. That's when the federal government should step in. Oh, and the federal government should provide national defense. That's it.

In this case, an argument could be made for government stepping in. By not getting vaccinated, they put others at risk that are allergic to or otherwise can't get vaccinations. So the government should force vaccination, or create a cost for those who choose not to.