Serosorting - or seroguessing?

Partners’ HIV status may, in fact, be a perception rather than a reality, and this has made HIV-prevention workers wary, to say the least, of promoting serosorting as a harm-reduction method.

An HIV-negative man basing a decision to serosort on whether a potential sexual partner believes that he is HIV-negative may be very problematic in terms of safety, yet there is evidence that many HIV-negative men are doing exactly this: increasingly disclosing and attempting to establish their partner’s status in casual, as well as committed, unprotected-sex situations.

An increase in HIV-negative serosorting, despite no increase in HIV testing, was reported from Scotland in a study published in 2005.¹ A survey of gay men from Edinburgh and Glasgow conducted in 1996, in a setting where only 50% of gay men had ever tested for HIV, found that serosorting was relatively uncommon. Amongst men who had unprotected anal sex with casual partners, 16% were sure they had only done so with men of their own status.

But by 2002 this had increased to 25%, despite no increase in testing in gay men. Since 2008, the proportion of Scottish gay men who have tested for HIV has increased to 75%,² and it will be interesting to see if this has influenced serosorting behaviour.

Researchers from Sydney³ looked at the serosorting behaviour of 300 gay men known to be HIV-negative between 2002 and 2005. Although there was an overall decrease in the amount of unprotected anal sex with casual partners over the course of the study, the mean number of casual partners who respondents described as ‘HIV-negative’ increased, from 6% in 2002 to 25% in 2005, and the proportion whose status was reported as unknown decreased from 85% to 60%.

Some perceptions of HIV status may be accurate and based upon discussion and disclosure between partners. However, a number of studies have found that many times when people claim to ‘know’ their partners’ status, they have actually not discussed it, but guessed it. Attempts to guess a partner’s HIV status, many studies have shown, give highly unreliable results, especially as many so-called ‘negotiations’ do not take place with words, and people’s HIV status is deduced by appearance or behaviour.

In the Seattle study by Matt Golden, quoted above,⁴ we noted that HIV-negative men were about half as likely to have serodiscordant unprotected sex as seroconcordant unprotected sex, and HIV-positive men were 7 to16 times less likely.

When the research was presented, Golden commented that: “Where the whole system breaks down, however, is where the other partner is of unknown status.” He found that partners were almost equally likely to have unprotected insertive sex if their own status or their partner’s was unknown as they would if they knew the sex was concordant.

At the 2007 AIDS Impact conference, Iryna Zablotska, of the University of New South Wales, introduced a new term – ‘seroguessing’ – for what a lot of gay men actually do.

She presented the results of two surveys⁵ showing that while unprotected sex between gay men increased by 25% to 33% during 2001 and 2005, serosorting behaviour increased by at least two-thirds: see How many people serosort? for more on this.

Serosorting, however, is crucially dependent on knowledge of the other person’s HIV status – and in this survey, especially amongst HIV-negative men, certain knowledge of a casual partner’s HIV status was very much the exception rather than the rule. Eighty per cent of HIV-negative men said at least some of their sexual encounters were with partners of unknown status. In the same context, only 38% of HIV-positive men said they always disclosed their HIV status themselves.

Zablotska then re-interviewed a subset of 427 gay men to find out whether their ‘knowledge’ of their partner’s HIV status was in fact knowledge, based on open discussion, or a guess. She found that a quarter of the HIV-positive men and 40% of the negative men who said they ‘knew’ their HIV partner’s HIV status had in fact guessed it.

She also found that, in HIV-negative men at least, the proportion of sex acts that were unprotected was actually higher when men guessed their partner’s status than when they had discussed it.

She found that, amongst men who had unprotected sex, if partners had neither discussed nor assumed their partner’s status, 30% of the sex had by HIV-positive men, and 34% of the sex had by HIV-negative men, was unprotected. If HIV status was overtly discussed, then 87% of the sex had by HIV-positive men and 58% of the sex had by HIV-negative men was unprotected.

But on the occasions when men assumed their partner’s status, then 78% of the sex had by HIV-positive men and 61% of the sex had by HIV-negative men was unprotected.

HIV-positive men were 5.2 times more likely to have unprotected sex if they knew their partner’s HIV status, and 3.2 times more likely if they assumed it, Zablotska said. And HIV-negative men were 1.9 times more likely to have unprotected sex if they knew their partner’s HIV status, and 2.1 times more likely if they assumed it – and they assumed it nearly twice as often as positive men.

Similar findings emerged from a community survey of gay men in Germany, which has already been cited above.⁶

Forty-eight per cent of the HIV-positive men and 44% of the negative men in this survey said they did try and find out, or at least guess, sexual partners’ status. HIV-positive men who did this either knew, or assumed, that their partner was negative 60% of the time and positive 40% of the time. Negative men only assumed their partner was positive 4.5% of the time; they must have made some inaccurate judgements as national surveys show that HIV prevalence in gay men ranges from 5 to 12%, according to region.⁷

So how did men assume that they ‘knew’ their partners’ status? Amongst the HIV-positive men, direct disclosure by the partner or reading it in an internet profile accounted for two-thirds of this knowledge when they assumed the partner was positive and 56% when they assumed they were negative.

However, a quarter of the time positive men’s assumption that their partner was also positive was based on the fact that they didn’t want to use condoms. When they assumed their partner was negative, a third based this on their partner’s appearance, or on verbal hints.

As for the HIV-negative men, on the relatively few occasions when they ‘knew’ their partner was positive this was usually due to direct disclosure: more than three-quarters of negative men who’d had a partner they assumed was positive made that assumption on the basis of disclosure in person or online, although 15% based it on appearance and 8% on the fact that the partner did not want to use condoms.

Three-quarters of the time negative men ‘knew’ their partner was negative because they said so. Knowledge of one’s status, however, is dependent on time since the last test and behaviour since then. But, as the researchers pointed out, fully a third of the men in the survey had never had an HIV test and 22% had a test result older than 18 months.

At the 2007 AIDS Impact conference, Jeanne Ellard⁸ presented qualitative data from a survey of recently diagnosed Australian men who were interviewed about: ‘Why I thought I wouldn’t get HIV’. She found that men used a lot of rationalisations to ‘talk themselves into’ unsafe sex.

One said he had persuaded himself HIV was rare: “I would think about all the times I’d had unprotected sex and was fine, and concluded that that showed there weren’t many HIV-positive guys in Sydney. I certainly didn’t know any.”

Another rationalised that ‘fit’ guys on the scene must be negative: “If they were HIV-positive, their quality of life would be lower and they wouldn’t be out partying.”

If someone overtly disclosed HIV status then sex was protected, but men more often used guesswork: “When you sense someone doesn’t want to use a condom, then it sends a little trigger to your head that he might be positive,” a participant said.

The 2002 UK Gay Men’s Sex Survey Out and About makes clear the false assumptions gay men make about other’s status, and underlines the disincentive many HIV-positive men have to disclose.⁹

Of the participants whose most recent HIV test was negative, two-thirds (65.3%) said they would expect an HIV-positive man to disclose his status before having sex. Even more men who had never tested for HIV had the same expectation (77%). In contrast, only just over a third of HIV-positive men expected that a partner would disclose their HIV status.

Forty-four per cent of HIV-negative or untested men said they would not want to have sex with the man who had just disclosed his HIV status to them – and this rose to 56% of men who had never had an HIV test.

The researchers comment: “Expectations that men with HIV will tell a prospective sexual partner their HIV status are still widespread. Over a third of men not tested [HIV] positive both expected a positive partner to disclose their status prior to sex and would not want to have sex with them if they did. In this climate, it is difficult to see what incentive men with HIV have for disclosing their status.”