Background: For women, the order of penile insertion, condom use, and ejaculation by orifice during sexual events affects the probability of HIV transmission and design of HIV prevention methods.
Methods: From October 2006 to June 2009, 431 women in Los Angeles and Baltimore in a rectal health study reported the sequence of penile insertion, condom use, and ejaculation by orifice location by computer-assisted self-interview. Multinomial logistic regression identified predictors of condom use by orifice among women who reported vaginal intercourse (VI) during their last anal intercourse (AI) event.
Results: Of the 192 reporting on a last AI event, 96.3% (180/187) reported VI. Of these, 83.1% had VI before AI. Including the 36% who ejaculated in both the rectum and vagina, 66% report any ejaculation in the vagina and 45% in the rectum. One-third used a condom for both VI and AI, <10% for VI only or AI only, and half used no condoms. After adjusting for race, partner type, and substance use, compared with women who used condoms for both VI and AI at last AI, being older (units = 5 years) [adjusted odds ratio (AOR) = 0.76; 95% confidence interval (CI): 0.60 to 0.96], with serodiscordant partners (AOR = 0.22; 95% CI: 0.08 to 0.61), and HIV-positive with seroconcordant partners (AOR = 0.15; 95% CI: 0.04 to 0.54) were associated with not using condoms.
Conclusions: For most of the women in our study VI accompanied AI, with AI usually occurring after VI. This evidence for use of multiple orifices during the same sexual encounter and low use of condoms across orifices supports the need for a multicompartment HIV prevention strategy.
*Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, CA;
†Division of Infectious Diseases, David Geffen School of Medicine, University of California, Los Angeles, CA;
‡Division of Global Public Health, Department of Medicine, University of California, San Diego, CA;
§Department of Mathematics and Statistics, California State University, Chico;
‖Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA;
¶Division of Clinical Pharmacology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD; and
#AIDS Research Alliance, Los Angeles, CA.
Correspondence to: Pamina M. Gorbach, MHS, DrPH, Department of Epidemiology and Division of Infectious Diseases, University of California, Los Angeles, Box 95-1772, Los Angeles, CA 90095-1772 (e-mail: email@example.com).
Supported by the UCLA Microbicide Development Program funding by the National Institutes of Health (NIAID IPCP No. 0606414), the Center for HIV Identification, Prevention, and Treatment (CHIPTS) NIMH Grant MH58107, and the UCLA Center for AIDS Research (CFAR) Grant 5P30AI028697.
Presented at Microbicides 2012 Conference, April 15–18, Sydney, Australia.
The authors have no conflicts of interest to disclose.
Received April 21, 2014
Accepted July 07, 2014