I'm not a virologist, but my understanding is that the lifecycle of HIV makes that unlikely. An individual must be infected with the virus in order for drug res

I'm not a virologist, but my understanding is that the lifecycle of HIV makes that unlikely. An individual must be infected with the virus in order for drug resistance to emerge; using PReP prevents infection from happening in the first place by stopping viral replication. HIV is quite hard to transmit – someone who is not infected or who is on a stable treatment regime can't transmit the virus to anybody, so resistance isn't much of a concern there. The bigger risk of drug-resistant strains emerging is due to poor adherence to medication regimes. Missing doses of antiretroviral therapy can cause drug resistance to emerge rapidly, as viral replication is no longer suppressed and HIV mutates like crazy.