Realising the potential impact of antiretroviral therapy
22 February 2013
The full results of a study on the effects of antiretroviral therapy in preventing new HIV infections have been published this week in the journal Science. The study, led by Professor Frank Tanser from the Africa Centre, spanned a seven year period (2004-2011), and followed nearly 17 000 people, the largest ever study completed at a population-level in a rural sub-Saharan African setting.
It was conducted in the sub-district of Hlabisa in the rural Province of KwaZulu-Natal, South Africa. The rolling hills of KwaZulu Natal are perhaps one of the most beautiful places on earth but it is also an area which has been particularly affected by the AIDS epidemic. KwaZulu Natal has one of the highest HIV prevalence rates in the world––one in four people over the age of 15 are living with HIV.
The province of KwaZulu Natal has been widely acknowledged as leading a strong provincial response to HIV. In Hlabisa for example, by mid-2012 the Hlabisa HIV Treatment and Care Programme had rolled-out antiretroviral treatment to more than 20 000 people across the area.
The 16 667 participants enrolled in the Professor Tanser’s study did not have HIV at the start of the trial and were regularly tested on average every two years. By the end of the study period 1 413 people had become infected with HIV. The people who tested HIV positive were offered antiretroviral therapy when they became eligible for treatment under national South African guidelines. Initially, adults with a CD4 count of <200 were offered treatment, this was extended to people with CD4 counts of <350, pregnant women and TB patients by April 2010.
What the study found was that the risk of acquiring HIV declined significantly if a person was living in an area where antiretroviral coverage was highest. For example in the areas where treatment coverage was between 30%-40% of all people living with HIV (which corresponds to about 60% of people eligible for treatment under current guidelines) people were nearly 40% less likely to become infected with HIV than in communities where coverage was much lower, at less than 10%. These results are yet further confirmation of the enormous impact antiretroviral therapy could have on morbidity, mortality and new HIV infections if access to treatment was scaled up to full impact levels in populations most affected by HIV.
This large scale population based study, the first in a hyper epidemic region in Africa, delivers powerful evidence that treatment is prevention and is an essential part of our combination prevention tool kit.
Bernhard Schwartlander, Director of Evidence, Innovation and Policy at UNAIDS
"This study is extremely significant. It is another piece in the puzzle that shows how treatment keeps people healthy and productive, and at the same time significantly reduces the likelihood to transmit the virus,” said Bernhard Schwartlander, Director of Evidence, Innovation and Policy at UNAIDS. “This large scale population based study, the first in a hyper epidemic region in Africa, delivers powerful evidence that treatment is prevention and is an essential part of our combination prevention tool kit.”
Concerns relating to the uptake of testing and treatment, retention, adherence, the development of drug resistance and other factors such as the capacity of health systems to deliver antiretroviral therapy have been long-debated, particularly since the findings of the HPTN052 trial were announced in 2011. The HPTN052 trial gave rise to great optimism amongst the HIV community––it showed that if a person living with HIV adheres to an effective antiretroviral regimen the risk of transmitting the virus to their uninfected sexual partner could be reduced by 96%. However larger, population based studies were yet to confirm how these findings apply to community settings.
While it is not unexpected that such a large scale and longer term population level study would pack the percentage punch of the HPTN052 trial, what it lacked in percentage points it made up for in the sheer scale and depth of the trial. What it has done is to bring us one step closer to finding out the true potential of antiretroviral therapy and the enormous impact it could have on preventing new HIV infections in real settings where HIV is part of daily life.
It has given further confirmation of the urgent need for rapid and wide-scale roll out of antiretroviral therapy to communities which have been most affected by the epidemic. And it has given yet another strong reason for countries to keep their commitments and meet the targets set out in the 2011 United Nations General Assembly Political Declaration on HIV/AIDS––to scale up access to treatment to reach 15 million people by 2015––and to halve the numbers of sexually transmitted HIV infections by 2015.