Brief Report: HIV Prevention by Australian Gay and Bisexual Men With Casual Partners: The Emergence of Undetectable Viral Load as One of a Range of Risk Reduction Strategies : JAIDS Journal of Acquired Immune Deficiency Syndromes

Secondary Logo

Journal Logo

Epidemiology and Prevention

Brief Report

HIV Prevention by Australian Gay and Bisexual Men With Casual Partners

The Emergence of Undetectable Viral Load as One of a Range of Risk Reduction Strategies

Holt, Martin PhD*; Lea, Toby PhD*; Mao, Limin PhD*; Zablotska, Iryna PhD; Prestage, Garrett PhD; de Wit, John PhD*,‡

Author Information
JAIDS Journal of Acquired Immune Deficiency Syndromes: December 15, 2015 - Volume 70 - Issue 5 - p 545-548
doi: 10.1097/QAI.0000000000000787
  • Free



A range of risk reduction strategies (RRS) is used by gay and bisexual men to reduce the risk of HIV transmission during anal intercourse with casual partners.1,21,2 The most well known is condom use, and the others include serosorting (matching HIV status before condomless sex), strategic positioning (HIV-negative men being insertive and HIV-positive men being receptive during condomless sex), withdrawal before ejaculation, and only having condomless sex with HIV-positive partners if they have an undetectable viral load.1–51–51–51–51–5 Trials have found that consistently taking antiretroviral medication [preexposure prophylaxis (PrEP)] can confer a high degree of protection to HIV-negative men.6,76,7 If consistently applied or sustained, condom use, an undetectable viral load and PrEP can be highly effective in preventing HIV infection, whereas the other strategies are generally less effective.6,8–126,8–126,8–126,8–126,8–126,8–12

The relative frequency of use of different strategies has been described among Australian, Swiss, and North American gay and bisexual men,1,13–151,13–151,13–151,13–15 suggesting that over three-quarters use some form of risk reduction during anal intercourse. In many countries, the most common RRS between casual partners remains condom use, with minorities reporting serosorting, strategic positioning, and withdrawal.1,13,14,161,13,14,161,13,14,161,13,14,16 Among men who have condomless sex with casual partners, serosorting tends to be more commonly practiced than strategic positioning or withdrawal.

The reported use of undetectable viral load and PrEP as strategies between casual partners remains rare. In Australian and Dutch studies, an undetectable viral load has been found to be associated with a greater likelihood of anal sex without condoms between regular but not casual male partners,1,4,51,4,51,4,5 and in Canada, 11% of “higher risk” gay and bisexual men used undetectable viral load as a strategy.15 The informal use of antiretroviral drugs as PrEP has been reported among small proportions (<3%) of gay and bisexual men in Australia and the USA.17,1817,18

In many countries, the HIV epidemic has resurged among gay and bisexual men.19 Attention has become focused on the potential of antiretroviral-based strategies to intensify prevention efforts, including in Australia's national HIV strategy.20 We therefore analyzed the range of HIV RRS reported by Australian gay and bisexual men with casual partners, taking into account the current emphasis on antiretroviral-based prevention.



The Gay Community Periodic Surveys (GCPS) are repeated, cross-sectional surveys of gay and bisexual men conducted in 6 jurisdictions in Australia. Surveys are conducted annually or biennially in most jurisdictions. Respondents are recruited by trained staff at gay social events and venues, sex-on-premises venues and clinics. Men self-complete a paper-and-pencil questionnaire, receive no remuneration for participation, and can participate in different years due to the cross-sectional design. The surveys monitor trends in sex and drug use practices associated with HIV transmission, and the uptake of testing and treatment for HIV and sexually transmissible infections. Details of the GCPS research design and key indicators are described elsewhere.21,2221,22 The GCPS have approval from the Human Research Ethics Committee of UNSW Australia.


Social, demographic, and behavioral variables were included to describe the sample.22 Whether participants had sex with casual male partners or not was ascertained with one question [Have you had any sex with casual male partner(s) in the last 6 months? Yes/No]. Condom use with casual male partners in the previous 6 months was assessed with 2 questions (I fucked him with a condom; He fucked me with a condom; never/occasionally/often). Participants are classified as engaging in consistent condom use if only anal sex with condoms is reported and no condomless sex is reported.22 Respondents who indicated “often” for either condom question were classified as frequently practicing condom use.

The use of noncondom-based risk reduction practices was prefaced with: “In the last 6 months, if you had anal sex without a condom with any casual male partner(s), did you do any of the following to avoid getting or passing on HIV?” The strategies were described as follows: serosorting (I made sure we were the same HIV status before we fucked without a condom), strategic positioning (“I chose to take the top role because his HIV status was different or unknown to me” for HIV-negative men; “I chose to take the bottom role because his HIV status was different or unknown to me” for HIV-positive men), withdrawal (When I fucked him, I chose to pull out before cumming because his HIV status was different or unknown to me; when he fucked me, I made sure he pulled out before cumming because his HIV status was different or unknown to me), PrEP (“I took anti-HIV medication before sex” or “I took anti-HIV medication after sex,” restricted to HIV-negative and untested men), and undetectable viral load (“When my partner was HIV-positive, I checked he had an undetectable viral load before we had sex” for HIV-negative and untested men and “I knew I had an undetectable viral load before we had sex” for HIV-positive men). Answer options were—never, occasionally, often, or always. We classified men as never/occasionally (infrequently) or often/always (frequently) using each strategy. Men were classified as frequently using withdrawal if they indicated that either they or their partners often or always withdrew before ejaculation.

Statistical Analyses

Chi-square tests and analysis of variance were used to compare the frequency with which each HIV status group engaged in comparable RRS. Statistical significance was set at P < 0.05. Analyses were conducted using SPSS Version 22.


Sample Characteristics

The survey was completed by 6161 men in 2013 (41.3% from Sydney, 38.0% from Melbourne, 17.9% from Queensland, and 2.8% from Canberra). Most of the sample was Anglo–Australian (65.8%), in full-time employment (64.6%), university educated (50.9%), gay identified (87.8%), and recruited from a gay community event or venue (80.7%). Of the 6161 men, 9.3% reported being HIV-positive, 75.6% HIV-negative, and 15.1% untested or of unknown HIV status. Of the 6161 participants, 1346 (21.8%) reported any condomless anal intercourse with casual male partners (CAIC) in the 6 months before the survey. Of the men who reported CAIC, 267 (19.8%) were HIV-positive, 933 (69.3%) HIV-negative, and 146 (10.8%) untested or of unknown HIV status. The characteristics of men who had CAIC are shown in Table 1, stratified by HIV status.

Participant Characteristics and Frequent Use of Different RRS by Men Who Reported Any Condomless Anal Intercourse With CAIC in the 6 Months Before Survey, by HIV Status

Use of RRS by Men Who Had Condomless Anal Intercourse

Among the 1346 men who reported CAIC, very few (1.3%) reported that they never practiced any HIV RRS during anal intercourse with casual partners. The 1.3% who never practiced any RRS were all HIV-negative or untested/unknown status men. A minority (23.6%) reported that they occasionally (but never often or always) practiced at least one RRS (16.9% of HIV-positive, 21.1% of HIV-negative, and 51.4% of untested/unknown status men who had CAIC, Χ2 = 72.48, P < 0.001). Seventy-five percent of the men who reported CAIC frequently practiced at least one RRS, and 41.2% frequently practiced at least 2 strategies. The most commonly reported strategy was serosorting, frequently practiced by 43.5% of men who had CAIC, followed by condoms (34.7%), withdrawal (21.2%), strategic positioning (20.4%), undetectable viral load (20.4%), and taking anti-HIV medication before or after sex (4.7%).

Table 1 shows the use of RRS by participants who reported CAIC, stratified by HIV status. Compared with HIV-negative and untested men, HIV-positive men were much less likely to report frequent condom use. HIV-positive men were more likely to report frequent serosorting than HIV-negative men but similarly likely to report strategic positioning. All 3 groups were equally likely to report frequent withdrawal before ejaculation. Small minorities of HIV-negative and untested men reported the frequent use of anti-HIV medication before or after sex. Most HIV-positive men said that they frequently relied on having an undetectable viral load, with much smaller proportions of HIV-negative and untested/unknown status men reporting that they frequently checked before sex that HIV-positive partners had an undetectable viral load.

Over three-quarters of HIV-positive and HIV-negative men reported that they frequently used at least one HIV RRS; untested and unknown status men were much less likely to report the frequent use of RRS (this is partly due to our classification system, which excluded untested men from strategies which required knowledge of their own HIV status). Over half of HIV-positive men and over 40% of HIV-negative men reported the frequent use of at least 2 different RRS. The most common combination of strategies was undetectable viral load and serosorting for HIV-positive participants (n = 101, 37.8%) and serosorting and condoms for HIV-negative participants (n = 178, 19.1%).


We analyzed the HIV RRS used by Australian gay and bisexual men with casual partners. Consistent with previous research,1,13–151,13–151,13–151,13–15 we found that three-quarters of men who engaged in CAIC reported the frequent use of at least one RRS. One quarter infrequently practiced risk reduction, potentially putting themselves at risk of acquiring HIV or transmitting it.

The RRS used varied considerably by HIV status. HIV-positive men were most likely to report the consistent use of at least one strategy during CAIC, particularly relying on undetectable viral load or serosorting. Having a sustained undetectable viral load dramatically reduces the risk of transmission,11,1211,12 although “viral blips” can occur during treatment.23 HIV-positive serosorting poses little risk for onward transmission unless the sex partners incorrectly guess or assume their partner's HIV status.8 Among HIV-negative men who had CAIC, the most common RRS was serosorting. HIV-negative serosorting is partially effective in preventing infection but much less effective than condom use because of the risk of undiagnosed infection or getting a partner's HIV status wrong.8,98,9 Untested and unknown status men who had CAIC were the least likely to consistently practise risk reduction.

Our data identify the common and deliberate use of undetectable viral load by HIV-positive men to reduce HIV transmission risk during casual sex. Echoing recent Dutch research,5 we cannot tell whether viral load is being discussed with HIV-negative casual partners before sex without condoms or whether it is being “unilaterally” used by HIV-positive men. However, similar to Canadian research,15 we found that 1 in ten HIV-negative and untested men frequently made sure that their HIV-positive partners had an undetectable viral load before sex without condoms. This suggests a growing awareness of “treatment as prevention” among Australian men who have sex without condoms, despite community skepticism about the concept.24 In contrast, the use of antiretroviral medication by HIV-negative and untested men remains relatively uncommon,18 perhaps reflecting the lack of formal availability of PrEP in 2013 in Australia.

Our findings are limited in a number of ways. Our aggregated, self-reported data meant that we could not examine the specific practices used with different partners or follow men to see how consistently they used RRS over time. Without clinical outcomes (eg, HIV diagnosis), we could not ascertain how effective each strategy (or combination of strategies) was in reducing the risk of infection. The frequency labels used in our questionnaire (never, occasionally, often, always) are relative measures and may have been interpreted in different ways by participants, depending (for example) on the absolute number of partners they had or what they considered a “normal” amount of sexual activity. This may have resulted in misclassification bias. Event-level data rather than aggregated measures would resolve some of these classification issues. Our sample is unlikely to be representative of all Australian gay and bisexual men, but it does provide a good representation of men at high risk of HIV (CAIC remains the primary transmission route for HIV in Australia).22,2522,25

Our analysis shows that most Australian gay and bisexual men use a range of strategies to reduce the likelihood of HIV transmission during casual sex. Having an undetectable viral load is now a commonly used strategy by HIV-positive men. Our results underline the current dynamic context in which HIV prevention is practiced. We encourage further investigation of relying on undetectable viral load as a RRS with casual partners, including whether its use is being discussed, and assessing the effectiveness of these strategies in reducing HIV transmission between gay and bisexual men.


1. Mao L, Kippax S, Holt M, et al.. Rates of condom and non-condom based anal intercourse practices among homosexually active men in Australia: deliberate HIV risk reduction? Sex Transm Infect. 2011;87:489–493.
2. Suarez T, Miller J. Negotiating risks in context: a perspective on unprotected anal intercourse and barebacking among men who have sex with men—where do we go from here? Arch Sex Behav. 2001;30:287–300.
3. Dubois-Arber F, Jeannin A, Lociciro S, et al.. Risk reduction practices in men who have sex with men in Switzerland: serosorting, strategic positioning, and withdrawal before ejaculation. Arch Sex Behav. 2012;41:1263–1272.
4. Van de Ven P, Mao L, Fogarty A, et al.. Undetectable viral load is associated with sexual risk taking in HIV serodiscordant gay couples in Sydney. AIDS. 2005;19:179–184.
5. Van Den Boom W, Stolte I, Witlox R, et al.. Undetectable viral load and the decision to engage in unprotected anal intercourse among HIV-positive MSM. AIDS Behav. 20132013;17:2136–2142.
6. Grant RM, Lama JR, Anderson PL, et al.. Preexposure chemoprophylaxis for HIV prevention in men who have sex with men. N Engl J Med. 2010;363:2587–2599.
7. Hankins CA, Dybul MR. The promise of pre-exposure prophylaxis with antiretroviral drugs to prevent HIV transmission: a review. Curr Opin HIV AIDS. 2013;8:50–58.
8. Jin F, Crawford J, Prestage GP, et al.. Unprotected anal intercourse, risk reduction behaviours, and subsequent HIV infection in a cohort of homosexual men. AIDS. 2009;23:243–252.
9. Golden MR, Stekler J, Hughes JP, et al.. HIV serosorting in men who have sex with men: is it safe? J Acquir Immune Defic Syndr. 2008;49:212–218.
10. Pinkerton SD, Abramson PR. Effectiveness of condoms in preventing HIV transmission. Soc Sci Med. 1997;44:1303–1312.
11. Cohen MS, Chen YQ, McCauley M, et al.. Prevention of HIV-1 infection with early antiretroviral therapy. N Engl J Med. 2011;365:493–505.
12. Rodger A, Bruun T, Cambiano V, et al.. HIV transmission risk through condomless sex if HIV+ partner on suppressive ART: PARTNER study. Paper presented at: Conference on Retroviruses and Opportunistic Infections; March 3-6, 2014; Boston, MA.
13. Balthasar H, Jeannin A, Lociciro S, et al.. Intentional risk reduction practices of men in Switzerland who have anal intercourse with casual male partners. J Acquir Immune Defic Syndr. 2010;54:542–547.
14. Snowden JM, Raymond HF, McFarland W. Prevalence of seroadaptive behaviours of men who have sex with men, San Francisco, 2004. Sex Transm Infect. 2009;85:469–476.
15. Bogowicz P, Moore D, Kanters S, et al.. HIV testing behaviour and use of risk reduction strategies by HIV risk category among MSM in Vancouver. Int J STD AIDS. 2015. Available at: Accessed March 2, 2015.
16. Velter A, Bouyssou-Michel A, Arnaud A, et al.. Do men who have sex with men use serosorting with casual partners in France? Results of a nationwide survey (ANRS-EN17-Presse Gay 2004). Euro Surveill. 2009;14:19416.
17. Holt M. HIV pre-exposure prophylaxis and treatment as prevention: a review of awareness and acceptability among men who have sex with men in the Asia-Pacific region and the Americas. Sex Health. 2014;11:166–170.
18. Zablotska IB, Prestage G, de Wit J, et al.. The informal use of antiretrovirals for preexposure prophylaxis of HIV infection among gay men in Australia. J Acquir Immune Defic Syndr. 2013;62:334–338.
19. Sullivan PS, Hamouda O, Delpech V, et al.. Reemergence of the HIV epidemic among men who have sex with men in North America, Western Europe, and Australia, 1996–2005. Ann Epidemiol. 2009;19:423–431.
20. Commonwealth of Australia. Seventh National HIV Strategy 2014-2017. Canberra, Australia: Australian Government Department of Health; 2014.
21. Holt M, Lee E, Prestage G, et al.. The converging and diverging characteristics of HIV-positive and HIV-negative gay men in the Australian Gay Community Periodic Surveys, 2000–2009. AIDS Care. 2013;25:28–37.
22. Zablotska I, Kippax S, Grulich A, et al.. Behavioural surveillance among gay men in Australia: methods, findings and policy implications for the prevention of HIV and other sexually transmissible infections. Sex Health. 2011;8:272–279.
23. Kanapathipillai R, McManus H, Kamarulzaman A, et al.. The significance of HIV “blips” in resource-limited settings: is it the same? Analysis of the Treat Asia HIV Observational Database (TAHOD) and the Australian HIV Observational Database (AHOD). PLoS One. 2014;9:e86122.
24. Holt M, Lea T, Murphy DA, et al.. Australian gay and bisexual men's attitudes to HIV treatment as prevention in repeated, national surveys, 2011-2013. PLoS One. 2014;9:e112349.
25. Zablotska I, Prestage GP, Middleton M, et al.. Contemporary trends in HIV diagnoses in Australia can be predicted by trends in unprotected anal intercourse among gay men. AIDS. 2010;24:1955–1966.

anal intercourse; Australia; gay and bisexual men; HIV prevention; HIV treatment; risk reduction strategies

Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.