Question: How effective are anti-retroviral drugs at making people with HIV non-infectious?
Paul Bellman: I think one of the critical issues facing HIV positive patients today in terms of their quality of life and also one of the critical issues in terms of creating the atmosphere that would be conducive to people being more willing to get tested and treated is the potential for the idea that some people who are HIV are not infectious. That could really be very liberating in terms of the whole community whether individual patients are non-infectious or not.
About two years ago a very prominent Swiss doctor, Dr. Bernard Herschel, chaired a committee that was sponsored by the Swiss government to determine whether or not what we called discordant couples where one partner is positive and the other partner is negative what the risks really were in terms of transmitting HIV. And particularly in an era where we could treat patients effectively, the question that they were addressing very specifically was whether or not someone, an HIV positive individual who is on effective treatment and had a very low undetectable viral load and as defined by Dr. Herschel for over six months, could transmit HIV to their negative partner whether or not they were practicing safe sex, which, you know, is the current standard in terms of HIV prevention between discordant couples and absolutely needs to continue to be so.
But this was an important question to address and their conclusion after looking at a series of scientific studies that were done just to track what happened to discordant couples and test the negative partner frequently is they couldn’t find any negative people who were turning positive even when the couples were acknowledging that they weren’t practicing safe sex. So that led Dr. Herschel to conclude that... to at least put forth a hypothesis that effectively treated patients might indeed be noninfectious and that created a lot of controversy and it also created some concern that, if misunderstood, it could lead people to relax safe sex precautions and that the paradoxical result could be more rather than less infections.
And the Center for Disease Control, which plays a very important role in public health policy in this country and gives great deal of considerations to all of its policy decisions basically said that yes, you know, reducing the viral load definitely reduces the infectious rate, but at this point you know we insist that people still follow and practice strict safe sex precautions.
Question: If treatment makes people with HIV non-infectious, could widespread treatment of HIV actually end the epidemic?
Paul Bellman: Well I think that the idea that treatment could potentially be prevention—because if someone is affectively treated they can’t pass on HIV—absolutely is powerfully important at this time where we don’t have a preventative vaccine and we don’t have a cure as actually the best path towards prevention. And Dr. Brian Williams of the World Health Organization who is one of their leading epidemiologists, has done some very careful modeling of the epidemiology of HIV in South Africa, which is incredibly hard-hit and he has calculated that if we could accelerate access to testing and effective treatment that we would dramatically reduce the incidence of new infection in the space of two decades—potentially even end the epidemic. But very early on it would translate into a dramatic reduction in new incidence of, not just HIV but infections that are associated with it like tuberculosis that are transmissible to non-HIV-positive people
Very recently, Dr. Ezekiel Emanuel who is Obama’s special advisor on AIDS had a blog in the Huffington Post which came out of the recent World AIDS conference in Vienna. And in this blog he was very critical of an activist who was critical of Obama’s current health plan in terms of budgeting for resources in the developing world. And, you know, so much so that he basically lambasted the activist and then went on to criticize Archbishop Desmond Tutu for similarly criticizing the Obama plan.
Now, these are really complex issues and certainly Dr. Ezekiel made some good points about how we have to try to make sure that the resources we’re spending are being well spent and I don’t think anyone would argue with that, but on the other hand he made a statement that I think really requires some scrutiny and should be the subject of real discussion and debate, and not just simply accepted. In this blog he said essentially that we can’t treat our way out of the epidemic and that is contrary to what many public health experts believe like Julio Montaner of Canada and Ronald Stahl of Pittsburgh who is a leading public health epidemiologist and it really is a matter of applying the resources and applying them wisely and correctly.
Question: What do you see as the most promising avenues of AIDS research?
Paul Bellman: One particularly promising avenue of research has come from the very careful study of a group of HIV-positive patients who have been positive for 20, 25 years and show little or no signs of immune compromise and have little or no detectable viral load. So, that suggests that there may be natural mechanisms that if we better understood could be harnessed as potential therapies. And here is where there has been some really interesting sort of cross-fertilization between basic science stuff that is happening in the sciences of immunology and what we’re observing in the clinic in patients and one particular scientist, Bruce Walker, has done some really good work sort of characterizing the molecular and cellular features of this group of patients who are long term non-progressors. And in fact, there are many research teams globally that are working on this problem and, just to be more specific, it appears that a certain kind of immune cell, which is a type of T-cell, not the T-cell that we conventionally think of as being infected by HIV, which is called the CD4 cell, but its complimentary or partner cell called the CD8 cell that there are certain... that those long-term non-progressor patients have very... you know their CD8 cells are great warriors and are able to kill viral, infected cells in the long term non-progressors. And so one can imagine that through further research we might be able to develop therapies that would further stimulate those cells to fight HIV and maybe even change patient status from people who would ordinarily progress to patients who could be treated with immune therapies and wouldn’t necessarily need to take toxic antiviral therapies indefinitely as the situation stands today.
So my vision actually in terms of at least from the point of view of a cure of HIV, from an immunologic point of view, is to treat patients with HAART, to treat them effectively, to get their viral loads to undetectable and then hopefully to develop cocktails of immune therapies that can mop up and take care of the rest of the virus—or prevent the virus from coming back. And that immune cocktail might be a combination of things that stimulate B-cells and certain T-cells and natural killer cells, similar to the antiviral drugs that work in some cases to interfere with a particular viral protein and then another viral protein and then the sum total of that allows there to be an effective therapy.
Recorded August 18, 2010
Interviewed by Max Miller