The 22nd International AIDS Conference: What You Need To Know

prevention. A few months ago, I posted case illustrating multiple ways HIV medicines can work for preventing new infections. In that case, a young woman had protected her child from being HIV infected at birth by consistently taking her medication. Her husband, who was not infected had opted to gain extra protection by taking PrEP (Pre-Exposure Prophylaxis). But that article allowed me an opportunity to introduce the concept of “Treatment as Prevention”.

Quite simply, that means if an HIV-infected person is consistently taking their medicines and the medicines are effectively suppressing the virus in the blood (undetectable) then that person does not transmit the virus to their partner. The rallying cry of the conference was U=U; Undetectable equals Untransmittable. We have seen increasingly more evidence to support that this is indeed the reality. A few years ago, some large studies with heterosexual discordant couples provided the first really good evidence of this.

In the study HPTN052 (HIV Prevention Trials Network), among heterosexual couples (male-female) where one individual was HIV-infected and the other partner not infected (serodiscordant couples), there were no cases of transmission to the uninfected partner when the infected partner was undetectable. The couples were not using condoms during sex. At the conference another important study provided reinforcement.

In a large study of serodiscordant male-male partners, there were almost 75,000 acts of condom-less sex. Out of all these sexual acts, there were NO transmissions between the undetectable partner on treatment and the uninfected partner. Now, to be totally accurate, there were a few individuals who did become infected. Importantly, they were not infected by their partners. Genetic analysis indicated that the virus they were infected with DID NOT come from their partner.

So they were infected by someone outside the relationship. A similar pattern was seen in the studies of heterosexual couples where a small number of infections were not caused by the partner on treatment. So, Treatment IS prevention.

This is very good news! So does this mean we can control the epidemic? The really big problem is that everyone who is infected is NOT on treatment. In the US, it is estimated that out of all infected individuals, there are about 15% who do not know they are infected. We can’t treat what hasn’t been diagnosed. Of those who