Thursday, May 14, 2009

HIV Information:Treatment as Prevention

The second plenary speaker was our own Dr. Julio Montaner, Director of the reputable British Columbia [BC] Centre of Excellence in HIV / AIDS at St. Paul's Hospital in Vancouver [shown below]; the current President of the International AIDS Society; Professor, Chair in AIDS Research and Head of the Division of AIDS, Department of Medicine, University of British Columbia and originator of many leading edge ideas, one of which is treatment of HIV/ AIDS as a way to prevent the further spread of HIV / AIDS. This idea is currently gaining some currency in other countries, notably Switzerland and was given, at least, lip support by the BC Premier as a campaign announcement [with no funding mentioned] in the first days of the re-election campaign that ended today with his third victory. [I have become somewhat cynical about the promises of politicians over the course of my adult life and, at no time more, than during my work in the HIV / AIDS arena.]
In the 28 years since the official start to the HIV /AIDS pandemic, further infections by the virus have been fought on a number of different fronts, but they have been unsuccessful in halting the spread of the disease. We have used education to make people aware of what is involved and to get them to change their behaviour. This has been mixed up by the conflicting messages. The safety message has been, ”Always use condoms”. But this has been consistently countered by those who do not want to talk about sex and sexual practices, usually compounded by their inaction and their refusal to let the young learn safer sex because that “is tantamount to giving permission for sexual expression.” !! The other conflicting messages have been those of a religious nature in concert with the above and saying “sex outside marriage is sin, contraception is sin, and anyway condoms don’t work - to the point of the RC statement that condoms have tiny holes in them that allow the virus though”, as I have noted previously ad nauseum. However, people, and particularly young people, still seem to be having sex with higher infection rates than those who were taught to play safe.

We have tried harm reduction, such as clean needle distribution for Intravenous Drug Users [IDU], sanctioned tattooing in prisons with sterile equipment and safe injection sites like the one [Insite] currently under the political gun here in Vancouver. We make only feeble attempts at the harm reduction that comes from providing the homeless with housing and food. Here is another effort that is fraught with mixed messages and lack of support because they are judged to sanction the “undesirable” behaviour of drug use as opposed to the goal of saving lives. The etiology of drug use is little understood or there might be a bit more empathic action by taking collective/societal responsibility for some of the conditions that lead to addiction instead of blaming only the addicts for their “weakness”.

The final prevention efforts have been exploration and development of technologies like the production of vaccines or microbicides. That effort came crashing to a halt in the past year when the one big hope for a vaccine ended in total failure and the scientific community agreed that it had to go back to the drawing board. We know that means at least ten more years before the next possible vaccine can be generated.

So how does treatment work as prevention?

First, we know that the two measures that indicate a PHA’s [Person with HIV/AIDS] relative health are 1] the T or CD4 cell count – the number of certain healthy immune fighter cells in the blood, and 2] the viral load - the amount of HIV virus that is in the blood. These factors generally work in an inverse ratio, i.e. when the viral load goes down the CD4 count goes up. These blood work counts are the measure of how well HAART [Highly Active Anti Retro Viral Therapy] is working in an individual with HIV.

The lower the amount of virus in the blood, the lower the infectivity of that person. HAART can reduce the amount of virus in the blood to undetectable levels, although we know that it does not eradicate it completely, and discontinuing HAART means the virus levels will shoot up again.

We also know that the lower the CD4 levels drop, the longer it takes to recover them and general immune strength. From below certain levels, it never completely recovers to former levels again. Science is also finding out that allowing levels to drop and then recover has very long term effects such as greater susceptibility to non-AIDS defining illnesses such as cardiac, liver and kidney problems and it, it seems, a plethora of other conditions. The conclusion is that it is best to try to keep the CD4 levels as high as possible. To that end, the International AIDS Society - US Guideline Committee recently recommended that HAART be started at a 350 CD4 count, up from the previously recommended 200 CD4 count. AND, it is now leaving it up to the individual doctors to determine if HAART should be started earlier if there appear to be pre-existing conditions. Many are recommending that, since without HAART, CD4 cell counts drop at a rate of about 100 per year. As the normal range of CD4 cells is from 500 to about 1300 and the long terms benefits of HAART are becoming more pronounced, why wait with HAART? Treatment now prevents serious long term illness in the future and their attendant high treatment costs. This is the way HAART works

The prevention part of the argument is based on the relative infectivity of the person. With HAART, the viral load drops on the first day that it is administered, stopping viral replication quickly. Undetectable viral load means very low infectivity to a non HIV + person, although not 100% as the virus does still reside in the body at some minimal and undetectable levels. We know that HAART works as prevention. It has been used for years to prevent transmission of the virus from an HIV+ mother to her baby during birth by putting her on HAART no later than the second trimester of pregnancy. These mothers do not breast feed their babies. Mother to child transmission in British Columbia is zero. Sero-discordant couples [one partner is HIV+ and one is HIV-] stay sero-discordant, when the infected partner is on HAART. And recently, we have a study in BC that shows a reduction in the spread of HIV when systems were set up for HIV+ addicts to get their HAART along with their methadone.

In the western world, it is estimated that about one quarter of HIV+ people have not been tested for HIV and do not know that they are positive. Given the information shared in the last post, doing more comprehensive testing in the higher risk populations and then treating the HIV+ people with HAART will reduce the transmission as well as offer better health possibilities to the people. In BC, by giving HAART to 2500 more PHA’s at a cost of up to $20 million annually, will result in 150 to 200 fewer infections per year. Each infection costs the medical system $250,000 to $750,000 over a lifetime – thus that prevention investment becomes a saving of lives, a great improvement in the quality of life of those treated and an economic saving of $37,500,000 to $150,000,000 for those 150 to 200 individuals not infected as a result of treatment.

What is the rationale and argument against treatment as prevention? Perhaps it is the short term gratification levels in the political system and that there is no political will to intervene on behalf of the marginalized!

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