This article says that there may be a “therapeutic” vaccine for Aids in 4ish years.
Do any such exist right now?
There is a vaccine for oral melanoma in dogs, suggested to be used as part of treatment. It’s been in use for about a year, it was licensed last year. Press Release from AMC, where research was done.
The rabies vaccine is effective post-infection, if you want to count that.
Would rho-gam shots count? You get them if you have Rh negative blood and have given birth to an Rh positive baby. It contains Rh positive antibodies and tricks the body into thinking that it already knows how to make Rh positive antibodies so that it doesn’t have to bother learning how to make Rh positive antibodies.
You don’t get better, you just don’t become a danger to any future Rh positive babies you might carry. That’s kind of therapeutic.