The infecting other people is mostly theoretical. As far as I know there is no actual instance of transmission from a person with an undetectable viral load on antiretroviral drugs to an uninfected person.
Thus, if someone is undetectable but then their treatment fails, they would become detectable and able to transmit the virus. But they could still infect someone else before they discovered their treatment failed.
Can you please put this into simpler terms? I am pretty confused. Because HIV transmission is not a theoretical and is not a myth. My understanding is, OP meant to say "transmission of HIV via known risky activities."
--EDIT--
Thank you for those clarifying. Often the unfamiliar technical terms can throw me off.
It's possible, with treatment, for people with HIV to have a viral load labelled undetectable.
To date, from an article I read, there have been no recorded transmissions from people with an undetectable viral load.
How many people taking retrovirals have undetectable levels of HIV?
Are those people using condoms?
http://www.aidsmap.com/No-one-with-an-undetectable-viral-loa...
Frequent testing and early intervention are very effective to achieving an undetectable viral load. The adoption of these as public health policy, as well as making available of prophylactic measures for at risk populations, has been effective at combating the spread of HIV - e.g. in San Francisco, where infection rate has been declining significantly over the last 5 or so years.
The studies on transmission are using sero-discordant couples who are not using condoms. The evidence/confidence has been building over time with multiple studies in which no transmissions were observed.
http://www.catie.ca/en/catienews/2016-09-06/negligible-risk-...
The HPTN 052 randomized study was halted early because the evidence so strongly favored the treatment arm. In the PARTNER observational study, no transmissions were observed in the study at all. The evidence is very strong.
> How many people taking retrovirals have undetectable levels of HIV?
According to my wife's doctor, most of them. And if that changes, they attempt to adjust treatment to return to that state.
BTW, undetectable appears to mean 20 copies of viral DNA per ml of blood.
> Are those people using condoms?
Well, we were, for many years. But we wanted children, and so after her doctor actually encouraged us we conceived them the old-fashioned way. I really, really enjoyed sex without a condom after so many years, I must say.
Now we have all the children we want, and we ought to go back to condoms, but I find myself wondering about the risk vs. reward. I suppose we'll go back to condoms, but I yearn to forgo them -- it's just less intimate. I wonder how other couples feel.
https://www.intomore.com/impact/cdc-acknowledges-that-undete...
Don't take my word for it though, would check with doctors.
They are saying that there are no recorded instances of someone that is taking antiretroviral drugs and has an undetectable viral load actually transmitting the virus.
Until a few years ago, C-section was recommended, but the current wisdom is that vaginal birth poses no greater risk for the baby.
Same with breastfeeding. Until a few years doctors would call CPS if a HIV+ woman admitted to breastfeeding her child. Now, our doctors encouraged my HIV+ wife to breastfeed.
OTOH she was the second (or third?) HIV+ woman in our city who dared to.
Worked out for us. Both kids are HIV-, as am I.