'Risk reduction' strategies don't always prevent HIV infection for gay men

Over a third of gay men with recent HIV infection due to unprotected anal sex contracted the virus after employing a “risk reduction” strategy, according to an Australian study published in the October 1^st edition of the Journal of Acquired Immune Deficiency Syndromes.

Some of the methods of perceived risk reduction mentioned by the men were serosorting, insertive unprotected anal sex, and receptive unprotected anal sex with an HIV-positive partner who reported an undetectable viral load. The investigators believe that their study shows that risk reduction is not a substitute for consistent condom use.

The number of gay men reporting unprotected anal sex with casual partners has increased in many countries since the mid-1990s. The extent to which this represents a true increase in the risk of HIV infection is uncertain because men often employ personal strategies to minimise their risk of becoming infected with HIV despite having unprotected anal sex.

Three principal strategies have been reported. The first is serosorting. This involves the selection of partners for unprotected anal sex who are known, or believed to be of the same HIV status. The second is strategic positioning. This means adopting the less risky role in unprotected sex, for example the HIV-negative partner having insertive sex with a receptive HIV-positive man or man of unknown HIV status. The third involves negotiation about viral load, with the HIV-negative partner agreeing to either insertive or receptive anal sex when their HIV-positive partner has an undetectable plasma viral load.

As it is uncertain how often gay men become infected with HIV after employing these strategies, investigators in Australia conducted a study involving 158 recently diagnosed with primary HIV infection.

The men were recruited in Sydney and Melbourne between 2003 and 2006 and were interviewed within eight weeks of their diagnosis and asked about the sexual risk activity they thought lead to their infection with HIV.

Of the 158 men in the study, 102 reported unprotected anal intercourse, and the investigators restricted their analysis to these men. Most of these men (63) believed that a casual partner was the source of their HIV infection.

Serosorting

Serosorting appeared to be widely practiced. Twenty-one (21%) men reported that they were certain that their partner was HIV-negative and18% said they suspected their partner was HIV-negative. Of the 21 men saying they were certain their partner was HIV-negative, ten said that this was a regular partner. The duration of the relationship was under twelve months in most of these cases.

Strategic positioning

Ten men (10%) reported that their highest risk behaviour was insertive unprotected anal sex. Of the 21 men who said that they were certain that their partner was HIV-negative, 20 (95%) reported unprotected receptive anal sex.

Viral load

A total of 21 men said that the viral load of an HIV-positive partner was known to them, and nine of these men said that their partner’s viral load was undetectable. All nine men reported receptive unprotected anal sex.

“On the basis of recent seroconverters’ retrospective accounts, serosorting was implicated in 21 HIV infections, strategic positioning in ten infections, and reliance on the undetectable viral load of an HIV-positive partner in nine infections. These 40 attributions of seroconversions to risk reduction strategies…represent 38% of all seroconversions in which unprotected anal intercourse was reported”, comment the investigators.

They believe that their findings have implications for the design of HIV prevention campaigns for gay men, “our data demonstrate that, not infrequently, risk reduction strategies seem to fail to prevent HIV infection on an individual level. This finding should be communicated to populations of gay men who might se these risk reduction strategies as an alternative to the more effective strategy of consistent condom use.”