Paper # 957
Use and Sharing of Antiretroviral Medications for Pre- and Post-exposure Prophylaxis to Prevent Sexual Transmission of HIV among High-risk, Substance-using Men Who Have Sex with Men in 4 US Cities
Gordon Mansergh*1, G Colfax2, D McKirnan3, B Koblin4, S Flores1, S Hudson5, and the Project MIX Study Group
1CDC, Atlanta, GA, US; 2San Francisco Dept of Publ Hlth, CA, US; 3Univ of Illinois at Chicago, US; 4New York Blood Ctr, NY, US; and 5Hlth Res Assn, Los Angeles, CA, US
Background: Pre- (PrEP) and post- (PEP) exposure
prophylaxis of HIV infection with antiretroviral medications are promising
interventions. However, efficacy data are not yet available. We examined recent
use and sharing of antiretroviral medications by men who have sex with men
(MSM) for the purposes of PrEP and PEP.
Methods: A convenience sample of MSM who reported
unprotected anal sex and substance use during anal sex in the previous 6 months
were enrolled in a behavioral intervention trial in Chicago, Los Angeles, New York City, and San Francisco; the men received a baseline and 12-month follow-up
assessment. In multivariate analysis, we examined baseline demographic
variables (age, race/ethnicity, education, city), sexual risk behavior
(unprotected anal sex: receptive, insertive, and combined), “Less concern for
HIV given effective treatments,” and PrEP and PEP use to prevent sexual
exposure in the previous 6 months, stratified by respondent HIV-status.
Results: In this study, 2% of HIV-negative men used
PrEP and 4% used PEP after a risky sexual encounter in the prior 6 months. 3%
of HIV-positive men gave PrEP and 4% gave PEP to partners after a risky sexual
encounter. Controlling for demographics and risk behavior at baseline, “Less concern
for HIV” predicted PrEP (OR = 5.5, 95%CI 1.1 to 27.6) and PEP (OR = 3.2, 95%CI 1.1
to 9.6) use by HIV‑ men at follow-up. No other variables predicted
antiretroviral use, including baseline sexual risk behavior. “Less concern for
HIV” was not associated with providing PrEP or PEP antiretroviral medications to
sex partners by HIV+ men.
Conclusions: Despite a lack of efficacy data, PrEP
and PEP antiretroviral medications are being used or provided by some MSM in an
attempt to prevent HIV infection. If efficacy is found, it is likely to be less
than that for male condoms (~95%), and a substitution effect of decreased
condom use could be a concern. Relevant research should help prepare for such a
scenario. Health officials and prevention providers should work to develop appropriate
risk-reduction messages, and related policy, training, and services to be
implemented once efficacy results are available.
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