Preefficacy Use and Sharing of Antiretroviral Medications to Prevent Sexually-Transmitted HIV Infection Among US Men Who Have Sex With Men

To the Editors: Preexposure and postexposure prophylaxis (PrEP and PEP, respectively) of HIV infection with antiretroviral therapy (ART) may reduce HIV infection through sexual contact.1 Although laboratory2,3 and mother-to-child4 transmission research have found that ART is effective in reducing HIV infection through nonoccupational exposure, human efficacy studies for preexposure prevention of sexual transmission are still underway. Men who have sex with men (MSM) will be a target population for ART prophylaxis if this strategy is found to be efficacious because they account for most HIV infections in the United States and are the only risk group with increasing incidence.5,6 We examined recent use and sharing of ART medications for the purposes of PrEP and PEP among high-risk substance-using MSM. A convenience sample of HIV-negative and HIV-positive MSM who reported unprotected anal sex and substance use during anal sex in the previous 6 months were enrolled in a behavioral intervention trial (Project MIX) in Chicago, Los Angeles, New York City, and San Francisco.7 Men participated in a baseline and 12-month follow-up assessment (2006-2008). In multivariate analytic models, we examined baseline demographic variables (race/ethnicity, age group, education level, city), unprotected anal sex, treatment optimism (ie, “less concerned” about HIV infection because of effective treatments), and PrEP (ie, used “before sex”) and PEP (ie, used “only after sex”) use to prevent HIV infection via sexual exposure within the previous 6 months. The analytic sample (n = 1011) consisted of men with data at the 12-month follow-up (84% retention of n = 1204 at baseline) and was diverse in terms of race/ethnicity (33% black, 18% Hispanic, 38% white, 11% other), age group (22% 18-29 years, 35% 30-39 years, 43% 40+ years), and education level (31% high school equivalency or less, 34% some post high school education, 35% college degree or more). Analyses were stratified by respondent HIV status (n = 454 HIV negative, n = 557 HIV positive). At baseline, two-thirds of the men (59% of HIV negative and 74% of HIV positive men, P < 0.0001) had engaged in unprotected anal sex during their most recent anal sex encounter (prior 3 months), and over one-third (35% of HIV negative and 39% of HIV positive men, P = 0.22) had unprotected anal sex with a partner of unknown or different HIV status than their own. We found that a small group of high-risk substance-using MSM reported ART prophylaxis use. PrEP was used by 2% (9 of 454) of HIV-negative respondents in the previous 6 months, and 2.5% (17 of 557) of HIV-positive respondents gave it to their sex partners to use. In comparison, PEP was used by 4% (18 of 454) of the HIV-negative respondents, and given by 4% (24 of 557) of HIV-positive respondents to their sex partners during the same period. This level of PrEP and PEP use is higher than reported by others.8-9 However, our sample consists of very high-risk MSM. Thirteen percent of HIV-negative and 24% of HIV-positive men (P < 0.0001) agreed at baseline that the availability of effective treatments had made them less concerned about HIV. Such treatment optimism has been associated with risk behavior among MSM.10,11 For HIV-negative MSM in our analysis, HIV treatment optimism at baseline was associated with PrEP use [adjusted Odds Ratio (OR) = 5.67, 95% Confidence Interval (CI) = 1.11 to 28.97) and PEP use (OR = 3.22, CI = 1.08 to 9.56) during the 6 months before 12-month follow-up, controlling for baseline unprotected anal sex and demographic variables. Similar results regarding treatment optimism, and PrEP and PEP use, were found for unprotected anal sex specifically with a partner of unknown or different HIV status than that of the respondent, a situation with very high risk for HIV transmission. In contrast, treatment optimism was not associated with HIV-positive MSM sharing PrEP or PEP with sex partners (P > 0.05). In a cohort of high-risk substance-using MSM, we found that PrEP and PEP antiretroviral medications were being used by 2%-4% of HIV-negative MSM or given to sex partners by a similar percentage of HIV-positive MSM in an attempt to prevent HIV infection. This is despite a lack of data showing that such ART use effectively prevents sexual transmission of HIV. Optimism about HIV treatment was predictive of later PrEP and PEP use for HIV-negative men and warrants further study. If PrEP use of ART is found to be effective in preventing sexual transmission of HIV, we may expect uptake in the use of this approach.12 However, early generations of ART prophylaxis could be less effective than the use of male condoms for anal sex, generally estimated at 90%-95%.13 In so far as high-risk MSM shift from condom use to ART prophylaxis, the introduction of this new strategy could have a net increase in overall risk for HIV transmission.14,15 Although earlier findings from a PEP feasibility study (that included risk-reduction counseling) did not suggest a shift in risk for most participants,16 other behavioral intent studies suggest disinhibition among high-risk HIV-negative MSM12; it is unknown whether behavior and HIV incidence will indeed change in MSM communities if PrEP is implemented and accessible. Research will be needed to determine the best behavioral messages and counseling approaches that combine condom use with ART prophylaxis. Health officials and prevention specialists must work to develop clear policy guidelines, community education for more complex prevention options, provider training, and related services for when efficacy results are available. ACKNOWLEDGMENTS The authors thank the study participants and staff. Project MIX Study Team: Atlanta-Steve Flores, Gordon Mansergh, David Purcell, Pilgrim Spikes, and Raekiela Taylor. Chicago-Kellie Dyslan, Carol Ferro, David Jamenez, Jenny Hopwood, Nicole Martin, David McKirnan, Chris Powers, and Pedro Rodriguez. Los Angeles-John Copeland, Lawrence Fernandez Jr, Bobby Gatson, and Sharon Hudson. New York-John Bonelli, Sebastian Bonner, Kent Curtis, Victoria Frye, Krista Goodman, Donald Hoover, and Beryl Koblin. San Francisco-Grant Colfax, Rob Guzman, and Tim Matheson. Gordon Mansergh, PhD* Beryl A. Koblin, PhD† Grant N. Colfax, MD‡ David J. McKirnan, PhD§ Stephen A. Flores, PhD* Sharon M. Hudson, PhD‖ Project MIX Study Team *CDC Division of HIV/AIDS Prevention, Atlanta, GA †New York Blood Center, New York, NY ‡San Francisco Department of Public Health, San Francisco, CA §University of Illinois and Howard Brown Health Center, Chicago, IL ‖Health Research Association, Los Angeles, CA