Richard Holbrooke should be commended for urging a renewed focus on global HIV prevention(“Still Losing the AIDS Fight”). Although HIV treatment and care programmes must be expanded, only by preventing new infections can we ultimately hope to turn back this devastating disease.

Holbrooke is also correct to emphasise the importance of HIV testing, especially for providing the main gateway into treatment. There is, however, little evidence that knowing one’s HIV status fundamentally alters behaviour. A few studies have found some modest changes in behaviour among those who test positive, but most trials unfortunately show that people who discover that they are not infected with the virus continue acting as they did before being tested — despite the obvious danger to themselves and to others.

The most rigorous study yet conducted, a randomised trial from Zimbabwe published last month in the journal AIDS, found an increased rate of HIV after people underwent testing and counseling compared with those who did not, though the increase was not quite statistically significant.

The London-based researchers noted that some other studies similarly have found “disinhibition,” or a worsening of behaviour, among people who learned they were not infected. While it might seem intuitive that knowing one’s HIV status and, ideally, receiving good counseling would lead to behaviour change and reduced risk, the real-world evidence for this conventional wisdom is still unclear.

Worse, those who have been recently infected are by far the most infectious, even though they generally do not test positive. A recent study from Uganda estimated that about half of all HIV transmission there was due to such “window period” cases.

HIV testing, in fact, does not appear to have played a crucial role in the declines in HIV rates observed in a number of countries and settings, including the US gay community in the 1980s; in Thailand and Uganda in the early 1990s; and more recently in Kenya, Zimbabwe, southern India, urban Malawi and Ethiopia. In most of those places, HIV testing facilities were scarce or even nonexistent during the period in which HIV rates fell fastest.

One of the biggest challenges for behaviour change is the practice common throughout much the continent of multiple “concurrent” partnerships. These relationships, typically involving longer-term, overlapping liaisons, result in closely linked sexual networks whereby HIV can spread rapidly throughout the population — even though most people do not have many sexual partners.

Another often neglected aspect of HIV prevention involves expanding family planning services, including for HIV-positive women who do not want to conceive. Reducing unintended pregnancies could greatly decrease the number of infected infants as well as the number of children who eventually become orphans.

Washington post