I suppose this is mostly aimed towards those on immunosuppressive medication.
The only thing I've ever worried about is chicken pox and with valid reasons as I used to work in a nursery school and now I live with a primary school teacher. General bugs and viruses don't really worry me as in, I don't go to lengths to avoid catching 'germs'.
I am now on Humira, MTX and leflunomide. Perhaps it's the combo but when Healthcare at Home came, they were very firm about infection risk and being careful such as; not eating raw fish. (I love sushi!!) My GP is also quite anxious and hands out antibiotics quite often if I show any sign of being unwell. I can't say it occupies a great deal of brain space though.