Hi Dakotasun, I'm not a medical professional, but in your situation, as long as there was no problem with the relationship with my boss, I would talk to them directly to ask what the process is. After all, the boss will be the person making the decision, or approving the process.
I don't imagine having a certificate from your Rheumy stating that you are immunocompromised would hurt, though I doubt it would be necessary - the prescription for the meds you take should be plenty of evidence for any medical professional.
I assume you are mostly thinking of other level 3/4 pathogens (but Ebola started of the discussion and thought train), because I'm here in West Africa and I'm pretty sure that consistent with all the advice from the Ebola experts, it won't spread the same way in any Western country, so there will not be an outbreak in your community (though there is about a one in 200 million chance of one or two patients in the hospital if someone actually makes it there on a flight).
The local community here has two wells, and 1000 people. For the WHO and CDC to get on world media and tell people Ebola in West Africa can be prevented by "simple" hygeine precautions like handwashing is truly ridiculous (what, you gonna walk 4km to the nearest well and back in 100F heat ten times per day to wash your hands?). And that's before we worry about the funeral rites where everyone in the family washes the body, and all the visitors hug it. And the fact that there is so much malaria, dengue, marburg, cholera, that all look just like Ebola in the early stages, that everyone in a medical facility assumes a presenting patient has one of those much more common illnesses, that are not infectious.
On this occasion, the WHO and CDC should take a good hard look at themselves and the way they initially treated the outbreak.
I'm going to take a deep breath now and get off my soapbox.
Apparently Influenza in droplets can last up to 24 hours on hard surfaces, so if you are worried about major pathogens, I'd think pretty hard about that one. I'd also guess you'd not want to be touching blood or body fluids from someone with weeping chicken pox or measles sores (now they KNOW Humira doesn't play nicely with either of those). So it sounds like a great idea to find out what the process is for any of those sorts of illnesses that will have a much bigger impact on you than on others.
I'd be really interested to hear what the outcome is once you find out - we are not in an Ebola country but are obviously prepping our workforce up for the possible spread here, so if you discover any medical rationale (different to the WHO advice) on risk management methods that you don't mind posting, can you reply here?