03:40am Monday 18 November 2019

What is HIV Treatment as Prevention?


As the 2015 International Aids Society Conference gets underway in Vancouver, B.C., researcher M-J Milloy outlines how Treatment as Prevention, a made-in-B.C. approach, has the potential to end the spread of HIV/AIDS.

What is Treatment as Prevention®?

Treatment as Prevention® (TasP®) is the idea – pioneered by Dr. Julio Montaner, the Director of the BC Centre for Excellence – that HIV treatment not only protects the health of individuals who are living with the virus, it also reduces the likelihood that they will pass the virus on to other people.

M-J Milloy

M-J Milloy

When people who are living with HIV are on effective antiretroviral therapy, that not only improves their health and the health of our communities, but it also reduces the number of new infections in communities. Through TasP® we will eventually, it is hoped, end the AIDS pandemic.

This concept was pionneered by Dr. Julio Montaner from the BC Centre for Excellence and UBC, and presented at the 2006 International AIDS Society Conference in Vancouver. It has since been taken up worldwide as a result of scientific results and findings, both from British Columbia and from other jurisdictions.

Has this strategy been widely adopted?

In traditional HIV treatment, you wait until a patient’s CD4 count—a measure of immune cells—goes down to a certain level. The World Health Organization has recently raised the CD4 threshold, which means more people are getting it earlier.

TasP® has been adopted as the standard practice in a number of jurisdictions around the world, including China, Brazil, Panama, the state of Queensland in Australia, parts of the U.S., Tanzania, and others. 

In these places, the idea is that the individual should be started on treatment as soon as is medically feasible for them without waiting until the CD4 count goes down to a certain level.

TasP® inspiredUNAIDS’ 90-90-90 strategy, which was adopted by the United Nations last September. The strategy sets new goals to end the HIV/AIDS pandemic by 2030. It says that by 2020, of all the individuals living with HIV in the world, 90 per cent should know whether or not they’re infected; of that 90 per cent, 90 per cent should be engaged in HIV treatment; and of that 90, 90 per cent should have no virus detected in their bloodstream, which means they can’t pass the virus on.

What are the barriers to TasP® being more widely adopted?

Some scientists and clinicians feel that if you start people on treatment too early, before the disease has really become apparent and symptomatic, they will not adhere to their treatment really well. That would result in more viral resistance to treatment.

Here in B.C., as more people have gone on treatment, viral resistance has in fact decreased. So people indeed do adhere to their treatments, and treatments are getting better.

The major opposition to bringing more people onto treatment remains cost. Countries are concerned about the cost of initiating individuals on anti-retroviral therapy. However we have produced very good evidence for B.C. that while the upfront costs may be higher than traditional methods, if you look at the economic effects of getting people onto treatment and getting them healthy and keeping them in the workforce, that makes it cost effective over the medium and long term. A recent study, published in the Lancet HIV, found expanding access to treatment in B.C. would save $66.5 million over the next 25 years.

Can you outline your recent research?

The study that I work on involves about 1,000 people who use illicit drugs, mostly from Vancouver’s Downtown Eastside and who are living with HIV infection. We looked at the CD4 count at initiation of treatment in individuals who started treatment between 2005 and 2013. 

In the early years of the study we saw that they were starting treatment relatively late. Their CD4 counts were on average below 200, which is the level at which people are believed to have AIDS. In later periods, 2010 and 2011, individuals started treatment at an average CD4 count of 400. This is much better from a medical and clinical point of view.

The second part of the study looked at how well people did on treatment, and we found that people who started earlier in fact had better responses to treatment and better than people who started later.

I think it’s important for us to be showing that it works among people who use illicit drugs, because they do bear a very heavy burden of the HIV/AIDS pandemic globally. There have been concerns expressed by many around the world that people who use drugs could not get onto treatment and stay on treatment.

M-J Milloy is presenting his research, Increasing rates of earlier antiretroviral treatment associated with elevated levels of optimal virologic response among HIV-positive illicit drug users during a treatment-as-prevention-based initiative in a Canadian setting, at the International Aids Society conference July 20, at 2 p.m.

VIDEO: Researcher M-J Milloy explains the science behind the Treatment of Prevention approach, and why it has the potential to eliminate HIV/AIDS.

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