When your not doing something with your body results in the harm of death of people other than yourself? The right to swing your fist has always ended at others nose. What we are litigating is not that concept well established but a still somewhat fluid understanding of the situation as it stands and how to apply our understanding of fact and law to the necessary choice between your autonomy and others safety.
Vaccinating someone who has already had covid is thornier and less clear. Medically it is certainly advisable a rerun isn't always mild and studies have shown individuals who are previously infected have twice the chance of reinfection compared to those who are also vaccinated.
The chance of misadventure from being vaccinated is fantastically low and the risk of reinfection while a lot smaller than in a naive individual is a long way from zero. I have substantial doubts regarding any immunologist would say
>and that it violates medical ethics to order unnecessary procedures.
Unless he had been in a coma and had just woken up yesterday.
What he is fighting for then is the right to undertake a course of action that is both meritless and brainless but I don't think we have a right to protect him from himself so the problem becomes is he risking others to an unacceptable degree. I'd say no. If he becomes infected he could infect others including the ample unvaccinated so he IS risking others by his actions but the risk is probably at this juncture small although this could change and he would be stupid to delay.
Importantly the test needs to be one with an acceptably low false positive rate performed by a legitimate lab. Not a self test for practical purposes lest people find a way to foul the test (see the soda issue where kids found out that an acidic liquid led to a positive test) or sell each other spit over the internet or something equally stupid.