Vienna: Drugs that repress HIV halved the
number of new cases of the AIDS virus, according to a study
published today ahead of the opening of the International AIDS
The findings support those who argue that antiretrovirals
-- which treat the human immunodeficiency virus (HIV) but do
not eliminate it completely -- are also a potent weapon for
preventing viral spread.
The paper looked at the population of the Canadian
province of British Columbia, examining coverage of
antiretroviral treatment and new cases of infection between
1996 and 2009.
Over this period, the annual tally of new cases fell by
52 percent, the researchers found.
For every 100 patients that were placed on the drugs, new
diagnoses of HIV fell by three per cent.
The paper, published in The Lancet, is authored by Julio
Montaner, director of the British Columbia Centre for
Excellence in HIV/AIDS in Vancouver, and president of the
International AIDS Society.
The time scale of the study dates back to the
introduction in 1996 of the triple HIV drug cocktail, which
now provides a lifeline for five million badly-infected
During the period under study, the number of people on
this combination therapy rose from 837 to 5,413 but the number
of new HIV diagnoses fell from 702 to 338 per year.
Concentrations of virus in the blood among treated
patients also fell sharply.
Antiretrovirals can reduce levels of HIV to below
detectable levels. The virus retreats to "reservoirs" such as
the lymph glands, where so far no way has been found to
eliminate it -- and if the drugs are stopped, it rebounds.
But having very low levels of virus also logically
implies a fall in the risk of handing on the pathogen to
Previous studies have also highlighted the indirect
benefit of antiretrovirals in preventing new cases of HIV.
As a result, some specialists say the time is near to
declare antiretrovirals a preventative tool, alongside the
condom, that should be added to the panoply of options for
preventing spread of HIV.