Three thought-provoking presentations at AIDS 2012 on Tuesday focused on key questions about pre-exposure prophylaxis, or PrEP: Do people know about it? Would they use it? And would they use condoms less often while taking it?
PrEP is one of the hottest topics here at the conference. This biomedical approach to prevention, in which HIV-negative people take antiretroviral drugs to avoid HIV infection, has been shown to help reduce HIV infection risk in multiple studies. Just days before the start of AIDS 2012, the U.S. Food and Drug Administration (FDA) approved the HIV medication Truvada to also be used as PrEP.
Of course, the success of any prevention method for any illness depends on people actually using it, so researchers are gauging interest in and attitudes toward pre-exposure prophylaxis as a way to help plan delivery of PrEP and safer-sex messaging around it.
Martin Holt of the University of New South Wales presented results from the PrEPARE Project
, which surveyed 1,283 men about their thoughts on PrEP. The vast majority (94.8%) identified as gay; 919 were HIV negative (71.6%), 122 were HIV positive (9.5%), and 242 did not know their HIV status (8.8%).
At the time of the survey, 17.5% of the men had heard of PrEP, and six men reported experimenting with antiretrovirals as "informal" PrEP. Based on survey responses, the researchers classified 28% of the men as willing to use PrEP; younger men were more interested than older men, as were men who reported recently having unprotected receptive anal sex ("bottoming") with casual partners.
Holt characterized the survey respondents as "cautiously optimistic" about using antiretroviral medications for HIV prevention, and warned against assuming that the potential recipients of new biomedical prevention tools "are as optimistic as the scientists" about their benefits.
Another survey, presented by Daniel Yang of the Johns Hopkins Bloomberg School of Public Health, assessed awareness of PrEP and attitudes toward it among transgender women and gay men and other men who have sex with men (MSM) in Chiang Mai, Thailand, one of the sites of the iPrEx study of PrEP. Not surprisingly, he noted, 66% of the respondents were aware of PrEP.
Survey participants were also asked whether they would use PrEP if it were shown to be 50% protective against HIV -- an approximation of the 44% overall efficacy seen in the iPrEx study (among iPrEx participants who took PrEP consistently, the efficacy more than doubled). In the Chiang Mai survey, 41% of MSM and 37% of transgender women reported they would be likely to use PrEP. Yang suggested that more of the respondents would have found PrEP acceptable if the survey had asked about a higher level of efficacy.
History of sexually transmitted infections and previous HIV testing were associated with willingness to use PrEP -- perhaps, Yang posited, because these individuals are already familiar with health care professionals. Respondents who reported planning ahead to have sex or having sex infrequently were also more accepting of PrEP; intermittent PrEP dosing, if proven effective, might be particularly beneficial to this population, Yang interpreted. He also noted that the transgender respondents expressed concern over potential interactions between PrEP and the hormone treatments they used; Yang stressed that, although MSM and transgender people are frequently lumped together for research purposes, they belong to distinct populations with different concerns and HIV prevention needs.
Another critical question about PrEP: Will people stop using condoms while taking it? The possibility of "risk compensation" or "behavioral disinhibition" has raised concerns that PrEP might do more harm than good if people ditch condoms while using it. In December 2010 and January 2011, roughly one month following the release of results from the iPrEx study, Douglas Krakower of Beth Israel Deaconess Medical Center and colleagues surveyed thousands of U.S. and Canadian members of an unnamed online "partner-seeking" network for gay men and other men who have sex with men, asking about their attitudes toward PrEP and whether they would use PrEP and condoms together.
A total of 5,035 men responded, of whom 19% had heard of PrEP. After a brief explanation of PrEP, 50% of the men said they would be likely to use it. Asked whether they thought they would skip using condoms while taking PrEP, 20% said they would for insertive anal sex ("topping") and 14% said they would for receptive anal sex.
Anticipated decreased condom use was linked with different characteristics. Those who said they would likely forgo condoms during insertive sex were more likely to have already done so during the past three months, and were also more likely to have been treated for substance use problems. Men who said they would skip condoms during receptive sex while using PrEP had higher perceived HIV risk and were more likely to have had unprotected sex after heavy drinking (at least five drinks) within the previous three months.
Based on these results, Krakower suggested that PrEP delivery should be accompanied by more intensive safer sex counseling for people with substance use issues and those who perceive themselves to be at high risk for HIV.
Want to learn more about PrEP? Start here.