Roger Tatoud wonders out loud about medicalisation of sex in OpenDemocracy but I would be more worried about medicalisation of health. PrEP operates by putting HIV negative people on antiretroviral (ARV) drugs in the hope that this will reduce their susceptibility to the virus. And 'treatment as prevention' advocates claim that putting HIV positive people on ARVs will ensure that they are less likely to transmit the virus to HIV negative people.
Both processes are part of what some claim is a new paradigm. However, treatment is not prevention. It may play a part in prevention programs but it is not thereby a prevention paradigm. And PrEP is of little use without other prevention measures, such as condom use. In fact, condom use on its own is probably just as effective as condom use in conjunction with PrEP.
I've only managed to see the first page of an article by Vinh-Kim Nguyen and others, entitled 'Remedicalising an epidemic: from HIV treatment as prevention to treatment is prevention'. But they seem to be arguing something along similar lines.
Prevention has long been underfunded and transmission rates are not declining in many countries outside of Africa. As for the African countries with declining transmission rates, it is not really clear why they are declining. Declines in incidence started long before most prevention programs came into existence. This was also long before significant rollout of ARVs.
But a few tens of millions of HIV positive people is not a big enough market for the pharmaceutical industry, they have to put tens, or even hundreds, of millions of people on drugs even though they are not sick.