Common...depends.
if you can take the "regular" HIV medicines, they will usually be covered.
If the doctor wants to put you on an experimental medicine, usually not covered. which may mean a death sentence for you unless you have the cash to get the medicine(s).
Also, if you happen to get on with a new insurance, they usually will not cover previous illness, so if you already had HIV, they most likely would not cover you...real nice...NOT