"And their tendency to revert upon infection to a new host" - Are you saying that viruses revert to some sort of "base version" when they transfer from host to host? I'd never heard of such a thing. How would that work?
Yes. Depends on the virus, but in the case of HIV infection, the patient can produce over 1 billion new virus particles a day. Given the size (10kb) and mutation rate (10-3 to 10-6, iirc) every single nucleotide is mutated every single day.
There's more to it than that (lookup "biological filter" for example), but the virus must mutate to avoid drugs, which usually means a fitness hit (lower replication, for example). Upon infection of a new host, the virus can quickly maximize fitness once again. Not a "base version" per se, but a more ideal, fit virus, without many/most of the escape mutations.
If that is the case, then would it be possible for someone who skipped a dose and development a resistant strain, to continue skipping doses until his virus looses its resistance?
New hosts don't take drugs that kill certain variants of the virus, so the version that does best in a drug free environment replicates quickest. That's usually different from the version that does best in the drugged environment.
