I'm in a similar situation.
I've got Crohn's Disease, which thankfully hasn't caused me any problems in 20 years, but that's because I take Mercaptopurine, an immunosuppresant.
When you get the vaccine at the pharmacy there is a paper with some not good things in regards to the vaccine. One of the things listed is Mercaptopurine being a problem.
I always try and avoid assholes, but that's no longer just about avoiding them because they're assholes. Now it's a medical issue so I have zero tolerance.
One good thing is that I have been able to eliminate a few friends-of-friends whom I never did like.
Edit: I wrote an article about breaking up with these folks., which pissed them off even more.