TO23 saidAs of now apparently the odds of transmitting the virus if you are on PrEP or if undetectable are virtually zero, but that doesn't mean that the virus won't evolve as time goes on. So I think people should reconsider how these new medications shouldn't be looked at as mediums to bypass a more proactive stance on sexual health and safety.
HIV is evolving. Literally different for every person.
"Each time HIV replicates (by infecting a new cell), small changes or mutations may occur.1 This means there are many different forms of HIV, including within the body of a single person living with HIV."- See more at: http://www.avert.org/professionals/hiv-science/types-strains#sthash.0jVoP2Vt.dpuf
There is HIV-1 and HIV-2. Hiv-1 is much more common. There are 4 strains of HIV-1 and 9 subsets. HIV has been a moving target for decades. Only with the three prong treatment, aka the "cocktail" HAART/ART therapy where it breaks the chain at different levels has it been successful. Virologic failure does occur between 5-10%. Mostly due to a failure of adherence. In most cases changing regimes can get them back to Undetectable.
PrEP is a two prong attack for Negative people, it doesn't need to have the third element in HAART to break up HIV reproduction because HIV hasn't been introduced to their body. It's DOA. To me that is the most proactive response.
With condoms there is still a potential for HIV to be introduced, from inaccurate use or failure. Google "condom efficacy anal sex"
"We are also unclear about to what extent condoms actually prevent HIV transmission in anal sex. This last fact may seem surprising, given that condoms have been recommended since the mid-1980s as the only effective HIV prevention method for gay men who have anal sex.
In fact, there is only one large study in gay men, dating from 1989. In this study of 2914 gay men, HIV incidence among those who said they used condoms 100% of the time was 70% lower than in men who did not use them at all. There has been one small study in the era of antiretroviral treatment (ART), which found an efficacy of approximately 75%." http://www.aidsmap.com/Consistent-condom-use-in-anal-sex-stops-70-of-HIV-infections-study-finds-but-intermittent-use-has-no-effect/page/2586976/51% of New HIV Infections from Condom Failure During Anal Sex, Study Finds
They further explain that, “condoms have been and should remain an important tool in our armamentarium for reducing the risk of HIV transmission among MSM.”
These findings also hold implications for the important role that pre-exposure prophylaxis (PrEP) may play in further reducing infections that may occur when condoms fail. PrEP is a prevention strategy where HIV-negative individuals take antiretroviral medications to reduce risk of HIV infection.http://betablog.org/51-new-hiv-infections-condom-failure-anal-sex-study-finds/