Preexposure prophylaxis (PrEP) is a promising HIV prevention strategy in which HIV-negative persons take antiretrovirals (ARVs) to prevent HIV infection.1 Clinical trials of the efficacy of PrEP started in 2005,2 and in November 2010 the iPrEx study reported the first evidence of the efficacy of oral PrEP among gay and other men who have sex with men and transgender women.3 This large-scale international safety and efficacy study reported that the daily oral use of a combination of tenofovir disoproxil fumarate and emtricitabine (marketed as Truvada; Gilead Science Inc, Foster City, CA) provided moderate and statistically significant protection and reduced the risk for HIV infection among men and transgender women who have sex with men by 44%. Overall levels of adherence to PrEP were rather low, and the detection of the study drug correlated significantly with prophylactic effect.4,5
As HIV diagnosis rates among homosexual men continue to rise in most country settings,6–9 mostly driven by trends in unprotected anal intercourse (UAI),10 PrEP has the potential to become one of the much needed tools to control the HIV epidemic in this population group. Therefore, in January 2011, shortly after the release of the iPrEx trial findings, the US Centers for Disease Control and Prevention issued interim guidance for clinicians in the United States on prescribing PrEP to high-risk homosexual men.11 In July 2012, Truvada was licensed by the US Food and Drug Administration for PrEP among HIV-negative individuals at high risk of acquiring HIV through sexual contact (including homosexual men and HIV-negative partners in serodiscordant relationships).12
In Australia, ARVs have been available as treatment for HIV-positive individuals since the late 1980s,13 but they have not been licensed for prophylactic use. However, ARVs are available through clinical services as postexposure prophylaxis (PEP) for individuals who report suspected exposure to HIV. Unregulated ARVs, including Truvada, can also be bought on various international websites. It is therefore possible for HIV-negative men in Australia to acquire ARVs for informal PrEP, including from people with HIV on treatment (ie, medication diversion), from a prescription for PEP, or from importing the medications from overseas.
Some willingness to use ARVs for PrEP has already been identified among HIV-negative gay and bisexual men in Australia, the United States, Canada, and elsewhere.14–17 Also, very low levels of nonprescribed or informal PrEP use by gay and bisexual men have been reported in North America.15,16,18–21 Virtually no PrEP use was observed in Australia before 2011.17,22 Here, we draw on behavioral surveillance data from Australia, collected in the year after the release of the results of the iPrEx trial, to describe the emerging nonprescribed use of PrEP to prevent HIV infection among Australian gay men.
Data Source and Measures
We used data from the Australian Gay Community Periodic Surveys (GCPS) conducted in 2011. The GCPS are repeated cross-sectional surveys that make use of convenience time–location sampling and recruit participants from gay venues, community events, and clinics in 6 Australian jurisdictions, mostly in their capital cities.23 Response rates range between 65% and 85%, and the samples predominantly represent men who identify as gay/homosexual (94% in 2011).
In 2011, the GCPS questionnaires incorporated a new section on the use of ARVs to prevent HIV infection. In particular, all respondents who did not identify as HIV-positive were asked the following: “In the past 6 months, have you taken any anti-HIV medication to prevent HIV infection: (1) before anal sex without a condom and (2) after anal sex without a condom (eg, PEP)” (yes/no for each). The term “PrEP” was not explicitly used in this questionnaire because the community advisory group suggested that gay men generally were not yet familiar with this term. We explored the extent and the possible covariates of preventive use of ARVs before UAI, including (1) sociodemographic characteristics (ie, age, education, and residential location); (2) gay social engagement, measured by the proportion of participants’ friends who were gay and the time participants spent with gay friends; (3) sexual practices [ie, number of partners, any UAI with regular (UAIR) and casual partners (UAIC)]; and (4) practices related to illicit drug use, such as using any drugs, injecting drugs, using party drugs for the purpose of enhancing sex, and having group sex after or while using party drugs [for each practice, responses were never, occasionally (once or twice), and regularly (at least monthly)]. All practices were assessed with reference to the 6 months preceding the survey. The construction of indicators of sexual practices has been described previously.23 We also explored the association between testing for HIV in the past 6 months and the preventive use of ARVs before UAI.
Associations were assessed using Pearson χ2 test with type I error of 5% and logistic regression models. Covariates of the preventive use of ARVs before UAI were first examined in unadjusted analyses. Covariates that were associated with the outcome of interest in univariate analyses (P < 0.10) were included in the multivariate analysis. We also assessed associations between covariates and identified a significant association between the use of party drugs for the purpose of sex and group sex after or while using party drugs: χ2(4) = 1800, P < 0.001. To avoid multicollinearity, only the latter variable was included in multivariate analysis. A “backward stepwise” approach was used to estimate the most parsimonious multivariate regression model. We present unadjusted odds ratios and adjusted odds ratios (AORs) and 95% confidence intervals (CIs). All analyses were executed using STATA 12.0 (StataCorp, College Station, TX).
In 2011, the GCPS recruited 7716 men in 5 states and territories, including 689 HIV-positive men, 5899 HIV-negative men, and 783 men of unknown HIV status. Of 6682 men who did not identify as HIV-positive, 3677 indicated that they had had anal intercourse in the 6 months before the survey and also responded to the question about the use of ARVs to prevent HIV transmission. Of these 3677 men, 92 (2.5%) reported taking ARVs before UAI to prevent HIV infection, of whom 61 (66.3%) also reported taking ARVs after UAI.
Table 1 presents further details regarding the characteristics and practices of men who reported any preventive use of ARVs before UAI. The extent of the preventive use of ARVs before UAI overall did not differ across jurisdictions; it was, however, more likely to occur in Queensland than in New South Wales (AOR = 2.48; 95% CI: 1.43 to 4.28). Preventive use of ARVs before UAI was lowest among men aged 30–49 years and highest among those who were <25 years old. However, differences across age-groups were not statistically significant in multivariate analysis. Men of non-European or of Aboriginal and Torres Strait Islander background were more likely than Anglo-Australians to report the use of ARVs before UAI to prevent HIV infection (AOR = 4.10; 95% CI: 2.36 to 7.13 and AOR = 3.22; 95% CI: 1.47 to 7.06, respectively).
Gay social engagement was not associated with preventive ARV use before UAI, but specific sexual practices were. Men who had >1 sex partner in the 6 months before survey were more than twice as likely to report preventive ARV use than men with only 1 partner. In comparison with men who did not report UAIR or UAIC in the preceding 6 months, men who reported having had UAIR only were no more likely to report preventive ARV use before UAI. Men who reported UAIC but not UAIR were significantly more likely to report preventive ARV use (AOR = 2.71; 95% CI: 1.44 to 5.07), as were men who reported both UAIR and UAIC (AOR = 2.36; 95% CI: 1.24 to 4.48).
Preventive ARV use before UAI was also associated with specific drug use practices, in particular regularly injecting drugs (AOR = 2.56; 95% CI: 1.03 to 6.36); using party drugs for the purpose of enhancing sex, occasionally (AOR = 2.23; 95% CI: 1.33 to 3.73) or regularly (AOR = 5.34; 95% CI: 2.99 to 9.56); and having group sex after or while using party drugs, occasionally (AOR = 2.42; 95% CI: 1.29 to 4.53) or regularly (AOR = 5.31; 95% CI: 2.62 to 10.76). There was no association between testing for HIV in the preceding 6 months and preventive ARV use.
In this sample of gay men who did not identify as HIV-positive, 2162 men were in regular relationships, including 120 men who reported having HIV-positive partners and 409 men who were in nonconcordant relationships in which at least 1 partner was of unknown HIV status. Preventive ARV use before UAI was reported by 1.9% of men with HIV-negative regular male partners, 1.7% of men with HIV-positive partners, and 4.7% of men with HIV status–unknown partners: Pearson χ2(2) = 10.81, P = 0.004. However, our data source did not clarify with which partners ARVs had been used. The length of the relationship with a regular male partner was also associated with preventive ARV use, which was 3.6% among men in a relationship of <6 months, 3.5% among men in a relationship of 6–12 months, 5.0% among men in a relationship of 1–2 years, and 1.1% among men in a relationship of >2 years: Pearson χ2(3) = 20.91, P < 0.001.
This analysis of behavioral surveillance data documents some use of ARVs as prophylaxis of HIV infection among Australian gay men in 2011, shortly after PrEP was proved efficacious among homosexual men. Notably, we observed that among sexually active gay men who did not identify as HIV-positive and had anal intercourse in the 6 months before the survey, 2.5% reported using ARVs before unprotected anal sex to prevent HIV infection. Thus far, similar low levels of use of ARVs for PrEP have been reported in some studies with gay men in the United States; no use of PrEP had been recorded in Australia before 2011.14,18–21 Therefore, these data can serve as a baseline for further monitoring of the preventive use of ARVs before UAI.
Our findings illustrate that the preventive use of ARVs before UAI among gay men is limited, and lower than the extent of PEP use among gay men in Australia, which, in 2010, was reported by 3.9% of participants in GCPS.24 Importantly, preventive ARV use before UAI was associated with specific sexual practices, including engaging in UAIC. It was also more likely among men who reported illicit drug use, particularly among men who injected drugs regularly and used drugs during sex. This suggests that the current use of ARVs before UAI is likely limited to specific groups or networks of homosexual men who engage in high-risk practices. Our findings are also in agreement with a recent study reported by Holt et al14 suggesting that willingness of gay men in Australia to use PrEP is highest among men who may benefit most of its use. This study in particular found that men who engaged in UAIC and perceived themselves at risk of HIV were most willing to use PrEP.14 Similar patterns of use and willingness to use PrEP in potentially high HIV risk contexts were found by Krakower et al15 in a US sample of homosexual men.
With regard to regular relationships, we did not find any clear indicators of a strategic preventive use of ARVs by HIV-negative men who had HIV-positive partners, possibly because of the small number of men in serodiscordant relationships included in the surveys. However, preventive ARV use was highest among men in HIV nonconcordant relationships, in which the HIV status of at least 1 partner was unknown. Preventive ARV use was also higher in relationships of shorter than longer duration. Encouraging HIV testing should be a priority whenever men do not know their own or their partners’ HIV status.
The findings presented here should be interpreted with an acknowledgment of the limitations associated with the design and conduct of cross-sectional surveys and collection of self-reported data, which may be prone to reporting bias. We also note that the GCPS predominantly recruit men who are involved in gay community social life25; the findings presented here can hence not be generalized to all men who have sex with men in Australia. A further limitation of our study is that PrEP was not explicitly defined in the questionnaire (a question was asked about the use of ARVs for HIV prevention before and after sex), and no information was collected regarding which ARVs were used, where they were obtained, and how often they were taken and for how long. We hypothesize that the ARVs used as HIV prophylaxis before unprotected sex may, at least in some cases, have been obtained as PEP prescriptions in Australia. Unfortunately, it is not possible in this study to disentangle informal PrEP use from prescribed PEP use because we did not ask detailed questions about the source of ARVs or their intended use. Further research is required to investigate the sources of ARVs used for the prevention of HIV infection.
Despite these potential limitations, our findings are of importance because they document what is likely initial informal use of ARVs for HIV prevention among gay men in Australia. In view of the recent findings by Holt et al14 that 28% of the participating gay and bisexual men are willing to use ARVs for PrEP, we anticipate that levels of informal PrEP use will increase. Furthermore, while Truvada is currently not available for PrEP through the Australian health system, it is now approved for prophylactic use in the United States12 and is likely to rapidly become more accessible and used, including in Australia.
The body of evidence is increasing regarding the potential merits of the use of PrEP for HIV prevention in different populations groups, including gay men.4,26,27 Our finding that preventive ARV use is associated with high-risk sexual practices raises important issues. In particular, although PrEP may be used when condoms are not, it also does not offer full protection from HIV.3 Furthermore, the preventive effect of PrEP is believed to be highly dependent on adherence to the prescribed dosing.3,28 In the absence of guidelines for the prescription of PrEP in Australia, and in a context of limited public discussion of its use, it is unlikely that men informally using ARVs for PrEP are achieving an optimum level of protection. Finally, the use of ARVs for PrEP by men with high–HIV risk behavior is currently at low levels, but it may indicate early and budding prevention optimism. Risk compensation has not been demonstrated in any PrEP trial so far, but some men self-report that they would be less likely to use condoms when taking PrEP.14 Further research is required to clarify why and how men are using PrEP, if they are engaging in risk compensation, and whether this will occur with real-world PrEP use in the future. Meanwhile, it is important to develop clinical and public health guidelines for PrEP use, train health practitioners, and educate gay communities about the appropriate and effective use of PrEP.
The authors acknowledge the key community partners—the state-based AIDS councils and people living with HIV/AIDS organizations in each state—for being instrumental in the conduct of the GCPS. They also extend their thanks to all study participants for sharing their life experiences with the research team.
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