The Institut national de la santé publique du Québec (INSPQ) has just published a consensus of experts that an undetectable viral load serves to reduce the risk of HIV transmission to “negligible or very low” for activities that would otherwise be considered high risk. This consensus is supported by a public health notice published by the Ministère de la Santé et des Services sociaux (MSSS). Of course, the consensus is based on a number of specifics, and it is important to understand the conditions to understand the consensus itself.
Six Necessary Conditions, with comments:
1. Stable and exclusive partners
The Consensus offers a vague definition of what might constitute a stable couple, mentioning that they would be “committed to one another” and refers to the HPTN052 study, which required that the couple exist for at least three months. Stability and exclusivity of the couple serve to eliminate uncertainty with respect to exposure to other STBBIs, especially in the context where the partners are being tested regularly. (In the HPTN052 study, there were transmissions of HIV, but outside the couple.)
2. No other sexually transmitted or blood-borne infection (STBBI)
We know that the presence of another STBBI can have an impact on viral load and on the chances of transmitting or contracting HIV, irritations and lesions offering entry points to the virus. The absence of STBBIs, then, offers more certainty with respect to maintaining an undetectable viral load and to other factors.
3. The seropositive partner has an undetectable viral load for at least two consecutive tests over a period of six months
Considering that most people living with HIV have viral load tests only every three or four months, the requirement of consecutive tests over a defined period serves to ensure a certain stability of the viral load. If there is a “blip” you reset the counter of months of undetectability to zero from the next undetectable result.
4. The seropositive partner has a medication adherence rate of 95% or more
This 95% figure should be very familiar: it is the adherence rate required to ensure that the virus doesn’t develop mutations that might be resistant to the components of the treatment regimen. Mutations and resistance lead to detectability and increased risk of transmission (not to mention the effect on the health of the person!).
5. Both partners have regular medical follow-up, with STBBI testing, viral load measures for the seropositive person and HIV tests for the seronegative partner
This condition follows as the guarantee of condition 2 and 3 (absence of STBBIs, undetectable viral load). A good medical follow-up also ensures that variations in the viral load will be caught and a transmission to the seronegative partner will be detected as soon as possible.
6. Both partners have appropriate and regular counseling, touching all the conditions named above, risk reduction, condom use and (for the seropositive partner) legal aspects and the possible consequences of not disclosing HIV status to a partner.
Counseling offers opportunities for the partners to receive information and to validate their understanding of the elements named above. In the long term, these counseling sessions will also allow the partners to hear about new scientific developments that might affect their evaluation of the risks they might be taking with their activities. Note that in the case of a couple responding to all of the above conditions, non-disclosure is not in question: the seronegative partners here are aware of their partner’s HIV status.
Why is the Québec Consensus important?
After the publication of the statement of the Swiss Federal Commission in 2008, public health authorities in many countries and provinces lost no time in distancing themselves from it, not ready to acknowledge that there were situations where they could affirm that the risk of HIV transmission is almost non-existent even in the absence of use of the classic prevention method, the condom. Since that time, research has continued and interest in the use of antiretroviral treatments as a means to reduce HIV transmission continues to rise.
The INSPQ’s Québec Consensus affirms not only what the Swiss Federal Commission stated in 2008, but also speaks of homosexual couples and different activities — oral, vaginal and anal sex — arriving at the same conclusion that with the observance of the conditions named and in the absence of condoms, risk is reduced to “negligible or very low”. Among all of the affirmations out there that it is important to start treatment earlier because it will reduce transmission, here, finally, is a benefit for those couples who meet all the criteria: they can forego the use of condoms without exposing themselves to greater risk of transmission between them.
The Consensus does not compare the effectiveness of condoms versus undetectable viral load — existing studies wouldn’t allow one to draw conclusions on that point. It does recognize that if not all of the conditions are completely respected there may still be a reduction in transmission risk compared to a detectable viral load, but the studies don’t allow us to quantify the reduction of risk in those cases.
And the other news we are hearing?
You may have heard about the interim report of the PARTNER study delivered at the CROI conference in the US. This research follows a large number of sex acts by study participants, with and without condoms, with and without STBBIs, between partners of opposite or same sex, and no cases of transmission. Let’s keep in mind that this is researchers sharing preliminary results from a study that is ongoing. In general, studies are designed to offer conclusions at the end and not the middle, but it does seem clear that the results so far are promising.
The other item that made the news recently was a consensus of Canadian experts on HIV and transmission in the context of criminal law in Canada. These experts are calling on the courts to recognize the state of science now and to better understand and interpret HIV transmission and the health consequences of HIV infection (which have evolved). According to them, interpretations based on incomplete or outdated information lead to injustice and this situation needs to be fixed.
The Québec Consensus, as my title suggests, is a guide to help serodifferent couples to reduce the risk of transmitting HIV between them, in consultation with their doctor. If the couple wishes not to use condoms as a means of prevention, this guide offers elements of medical follow-up and testing that can help them make decisions together to avoid HIV transmission.
For me, the Québec Consensus is an important step forward. It is an official pronouncement based on available proof that affirms the conditions in which a couple can have confidence that transmission is very unlikely, whether their choice of prevention strategies includes condoms or not. Public health bodies are by their nature reticent to make liberal and permissive statements about evaluating risk. In other words, they tend to be conservative. They don’t allow themselves to make the kinds of announcements that a researcher might make about preliminary research results or that a group of experts speaking on their own behalf can do.
We can hope that the other items will also prove to be reliable in scientific terms, confirmed by other studies carried through to their conclusions. The Québec Consensus is the step forward that gives me confidence that our public health structures will recognize the validity of new evidence and will act to integrate it into our “official” understanding of HIV and its transmission. Here’s to the scientific method!