Anti-retrovirals are currently prescribed only when HIV has begun to damage the patient's immune system

Flickr/MikeBlyth

Clinical trials of a universal 'test and treat' strategy that could see the HIV pandemic halted within 5–10 years are soon to begin, the American Association for the Advancement of Science meeting in San Diego heard yesterday (21 February).

Small-scale trials in Canada, South Africa and the United States will examine the assumption that testing everyone in a target population, and giving antiretroviral drugs (ARVs) immediately to those who are positive, will stop transmission of the disease, Brian Williams of the South African Centre for Epidemiological Modelling and Analysis told the meeting.

Modern ARVs vastly reduce the amount of HIV in the blood — by about 10,000-fold, said Williams. In doing so, they reduce infectivity by about 25-fold, and Williams and colleagues have calculated that if all HIV patients took them, transmission of HIV would stop within five years.

The strategy would be expensive — US$3–4 billion a year for South Africa alone — and would rely on people's willingness to be tested and take a lifelong course of drugs, said Williams.

There are also fears that such mass drug treatment would increase drug resistance to ARVs (see 'Test and treat' HIV strategy could backfire) although there is evidence that patients are developing less resistance to the latest ARVs than they did to first-generation drugs.