'ART as prevention tool' policy announced for British Columbia

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The western Canadian province of British Columbia will implement a new, aggressive strategy to expand antiretroviral coverage in order to curb new HIV infections, B.C.’s health minister, George Abbott, announced today. The new policy is based on a mathematical model from the B.C. Centre for Excellence in HIV/AIDS, published in the July 1st edition of the Journal of Infectious Diseases, and when implemented as early as this autumn, will be the first time that anti-HIV treatment has officially been used as an HIV prevention tool.

The mathematical model, reported here, calculated that expanding antiretroviral therapy (ART) to everyone diagnosed with HIV with a CD4 count below 350 cells/mm3, would have a pronounced effect on transmission, by reducing viral load on a population level. The model assumed that ART as prevention would be used as an adjunct to other HIV prevention tools – such as condoms and needle exchange programmes – and would also occur amid a background of increased uptake of HIV antibody tests. Under these circumstances, expanding ART rollout would prevent more than two-thirds of all projected new HIV infections in British Columbia by 2030.

The man behind the study, and the new strategy, is Professor Julio Montaner, director of B.C. Centre for Excellence in HIV/AIDS, and president-elect of the International AIDS Society, who is a vocal proponent of the use of ART as a prevention tool – in 2006 he co-authored a study based on mathematical modelling which concluded that providing ART to everyone in the world infected with HIV would stop the HIV epidemic in its tracks within 50 years.


mathematical models

A range of complex mathematical techniques which aim to simulate a sequence of likely future events, in order to estimate the impact of a health intervention or the spread of an infection.

coronary artery disease (CAD)

Occurs when the walls of the coronary arteries become narrowed by a gradual fatty build-up. It may lead to angina or heart attack.


Cost-effectiveness analyses compare the financial cost of providing health interventions with their health benefit in order to assess whether interventions provide value for money. As well as the cost of providing medical care now, analyses may take into account savings on future health spending (because a person’s health has improved) and the economic contribution a healthy person could make to society.

"The more people you treat, and the faster you engage people in treatment, the greater impact you will have on the epidemic," Prof. Montaner told today’s Vancouver Sun newspaper.

The public health benefit of ART – by reducing viral load on both a population and individual level – has long been discussed, but never before been explicitly used as a prevention tool. Even the recent controversial statement from the Swiss Federal AIDS Commission – which stated that individuals on ART, who have had an undetectable viral load in their blood for at least six months, who adhere to treatment, and who do not have a sexually transmitted infection, should not be considered infectious to their sex partners – did not recommend a change of Swiss policy regarding ART as a prevention tool.

Consequently, Health Minister George Abbott told the paper: "This would be leading-edge from a global perspective, not just a Canadian perspective."

It is estimated that up to 15,000 individuals are infected with HIV in British Columbia, of whom 27% are thought to be unaware of their infection. However, as of May 2008, just 4,379 were on ART even though all drugs are available in the province free of charge.

The majority of individuals who have not taken up ART, despite being eligible, are thought to be people on low incomes, aboriginal Canadians living in remote communities, as well as HIV-positive injecting drug users, some of whom are also homeless and/or mentally ill.

Both Prof. Montaner and minister Abbott admitted in today’s newspaper story that expanding ART to these populations will be difficult, and the new strategy may include paying individuals to take their treatment as prescribed.

The lifetime cost of treating one individual with HIV in Canada is estimated to be between CAD$250,000 and CAD$750,000, and the study suggests that the new strategy could save up to CAD$95 million over 25 years. Although the programme will be costly in the short-term, the B.C. health minister noted: "It's far more cost-effective to prevent disease than it is to treat disease.”

April’s edition of HIV Treatment Update examines the effect of ART on transmission, and includes a discussion of the use of ART as a prevention tool. It can be downloaded here.