Viral load increasingly features in safer-sex discussion and decisions by HIV-positive gay men and their partners

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A Dutch study presented at the Tenth AIDS Impact conference this week showed that HIV-positive gay men are increasingly taking viral load into account when it comes to deciding whether to use a condom during sex.

Another study from the USA (Horvath) also showed that when they were in a situation where they knew they were with an HIV-positive partner, HIV-negative men were also discussing their partner's viral load and basing condom use decisions on it. It also found that the minority of HIV-positive men in the study had disclosed their status and discussed their viral load with to most of their sexual partners.

However this study also found that disclosure and discussion of HIV status between men with differing HIV status was quite rare. Although viral load was discussed more often than not if HIV-negative men did know their partner was positive, they usually were not aware or chose not to have sex at all or chose not to have sex once they found their partner had HIV.


unprotected anal intercourse (UAI)

In relation to sex, a term previously used to describe sex without condoms. However, we now know that protection from HIV can be achieved by taking PrEP or the HIV-positive partner having an undetectable viral load, without condoms being required. The term has fallen out of favour due to its ambiguity.


In HIV, refers to the act of telling another person that you have HIV. Many people find this term stigmatising as it suggests information which is normally kept secret. The terms ‘telling’ or ‘sharing’ are more neutral.

Swiss statement

A 2008 article by a group of Swiss doctors which asserted that people living with HIV who are taking antiretroviral therapy and have an undetectable viral load, with no sexually transmitted infections, do not pass on HIV to their sex partners. Since then, major scientific studies have proven that the statement was correct.


The presence or absence of detectable antibodies against an infectious agent, such as HIV, in the blood. Often used as a synonym for HIV status: seronegative or seropositive.

statistical significance

Statistical tests are used to judge whether the results of a study could be due to chance and would not be confirmed if the study was repeated. If result is probably not due to chance, the results are ‘statistically significant’. 

A third survey from France (Rojas Castro), conducted by the national HIV organisation AIDES, found that a majority of HIV-positive people surveyed were aware of the 'Swiss Statement', the statement released by the Swiss Federal Commission on HIV and AIDS in January 2008 (Vernazza) which declared that under carefully-defined parameters, people with HIV with stable undetectable viral loads 'were not' infectious. It found that knowledge of the statement was associated with better health, less difficulty disclosing HIV status, and having a better sex life.

The Dutch study

The Dutch study was a survey of 212 gay men with HIV who were recruited through a 307-member online discussion forum of the Dutch HIV Association. These 212 completed an online questionnaire on unprotected anal intercourse (UAI) and so-called 'viral sorting' practices. One interesting aspect of the study was that the median age of participants was 48.

Of the 212 men, 177 (83.5%) were on treatment with an undetectable viral load, and of these 177, 120 (68%) had had unprotected anal sex since their HIV diagnosis.

These 120 were asked “Did you decide to have UAI because your viral load was undetectable?” Fifty-three of the 120 (44%: 30% of all virally undetectable men and 25% of all HIV-positive men) had ever practised viral sorting with an HIV positive partner and 46 (38%: 26% of all undetectable men and 21% of all positive men) with an HIV negative partner.

The men who had had UAI were also asked if they had done it with a casual partner (a one-night stand), a 'sex buddy' (someone they saw regularly but did not regard as a boyfriend) or their regular partner. Twenty-four per cent had had UAI with a casual partner, 17% with a sex buddy and 29% with a boyfriend.

Among men who had had UAI with an HIV-positive partner, 20% of those with a casual partner, 58% with a sex buddy, and 45% with a steady partner had taken their and/or their partners' viral load status into account when deciding not to use condoms.

Amongst those who had had UAI with an HIV-negative partner, 57% had taken their own viral load into account when deciding to have UAI with a casual partner, 40% with a sex buddy and 64% with a steady partner.

The numbers of men in each partner class were too small to make these differences between partner type statistically significant; it is just worth noting that 'viral sorting' means very different things between serodiscordant and seroconcordant partners. The participants reported that they had disclosed their status to their partners in most cases, though we have no means of verifying this.

Presenter Wijnand van den Boom of the Amsterdam Public Health Service said: “We conclude that viral sorting as a risk reduction strategy is consciously practised relatively frequently among HIV-positive MSM.”

However he warned that “since most of the available data on viral load and HIV transmission risk is derived from studies on heterosexuals, future investigation should provide evidence on the effectiveness of viral sorting as an HIV risk reduction strategy in lowering HIV transmission among MSM.”

The US study

The US study was a survey of a very different gay population. It was an online survey of 326 gay men aged 18+ and was largely designed to look at their use of pornography, but the researchers incorporated questions on serostatus, unprotected sex and viral load in their questionnaire. It asked whether, in the last 90 days, participants had had UAI with a regular partner, a casual partner, or a 'repeat casual partner' (defined as someone they had had sex with more than three times).

It asked about serostatus and whether, in situations where participants knew that they, their partner or both of them had HIV, whether the positive person/s had talked about treatment and, if they were on treatment, whether they had talked about their viral load. It then looked to see how many participants who discussed viral load had gone on to have UAI.

Dr Keith Horvath of the University of Minnesota told the conference that this was a typically white, well-educated group of gay men with an average age of 32. Only 22 of the 326 participants (7%) said they were HIV positive. Another 10% either said they did not know their HIV status or chose not to disclsoe it, and it's possible the majority of these had HIV. Either way, and the small number of declared HIV-positive participants means that it's difficult to draw statistically significant conclusions from this survey.

Viral load was discussed in 13 out of 14 (93%) of steady relationships where at least one partner had disclosed HIV, and in six cases out of the 13, the partners had UAI.

HIV status was disclosed in all 15 relationships between 'sex buddies' where one of the partners was HIV positive, and antiretrovrial therapy between seven of them. In the three partnerships where thsi les to a viral load discussion, UAI occurred two times, but in the four cases where viral load was not discussed, UAI happened every time.

In casual partnerships (one-off or up to three repeats), viral load was discussed in nine out of 17 sexual episodes (53%) where at least one partner had disclosed HIV, and five out of nine (56%) involved UAI. However in cases where viral load was not discussed, UAI occurred in 75% of encounters.

This survey shows encouragingly high levels of disclosure by men with HIV of both their seroststus and their viral load. It also shows that when partners know each others' HIV status, more often than not viral load also gets discussed. Discussing viral load may possibly lead to slightly more, rather than fewer, decisions to use condoms, but nonetheless only results in partners deciding to have UAI about half the time.

Any conclusions about disclosure, however, must be tentative because of the low number of men in this survey who acknowleged having HIV. The biggest barrier to using viral load in decisions whether to have safe sex, Dr Horvath said, was the very low overall level of disclosure and discussion of partners' serostatus revealed by the survey.

The French survey

The survey on the Swiss Statement conducted by AIDES was filled out by 2356 people, 977 of them people with HIV (42%), who had been in contact with AIDES in October 2010.

Focusing solely on the people with HIV, 57% reported knowing about the statement, more than half of who had heard about it from HIV organisations and 25% from friends with HIV. People who knew about the Swiss statement were more likely to have an undetectable viral load and to have a CD4 count over 350 cells/mm3. This probably reflects longer time on treatment.

Having heard about the statement was associated with positive psychological effects. Thirty-one per cent reported “less fear of transmitting HIV” and 55% “less difficulty speaking about HIV with sexual partners.” Fourteen per cent said their sex life had improved and 15% reported better adherence to HIV treatment. However knowing about the statement produced no overall change in condom use: 13% said they used condoms less after hearing about the statement but 11% used them more.

Presenter Daniela Rojas Castro commented that it should not be necessarily concluded that knowing about the Swiss statement had directly produced the effects seen; knowing about it could be a surrogate for having a better sense of belonging to an HIV-positive community.


Van den Boom W et al. Frequent use of viral sorting by HIV-positive MSM: the consideration of viral load when deciding to engage in unprotected anal intercourse with HIV-positive, HIV-negative and status unknown partners. Tenth AIDS Impact conference, Santa Fe, New Mexico. Abstract 172. 2011. [NB the original title of this study as listed online has changed]

Horvath K et al. Discussions of viral load in negotiating sexual episodes with primary and casual partners among men who have sex with men. Tenth AIDS Impact Conference, Santa Fe, New Mexico. Abstract 111. 2011.

Rojas Castro D et al. The Swiss Statement, who knows about it and what are its effects on PLWHIV? Results from the “VIH, Hépatites et vous” Survey.Tenth AIDS Impact Conference, Santa Fe, New Mexico. Abstract 359. 2011.

Vernazza P et al. Les personnes séropositives ne souffrant d’aucune autre MST et suivant un traitment antirétroviral efficace ne transmettent pas le VIH par voie sexuelle ('The Swiss Statement'). Bulletin des Médecins Suisses 89 (5), 2008.