Reducing risk exposures to zero and not having multiple partners: findings that inform evidence-based practices designed to prevent STD acquisition.

Our objective was to assess prospectively the relative contribution of reducing penile-vaginal risk exposure to zero and limiting the number of sex partners to one, on the acquisition of biologically confirmed sexually transmitted disease (STD) among African American women adolescents. Data from a prospective cohort of 522 African American women adolescents enrolled in an HIV prevention trial were used. Baseline STD testing and single-dose directly observable treatment provided an infection-free cohort, who were followed and assessed at six-month intervals. Self-administered vaginal swab specimens were tested for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis at baseline, six, 12, and 18 months. Frequency of having multiple sex partners and unprotected vaginal sex over each six-month assessment interval was measured. Adolescents who reported multiple sex partners, relative to only one partner, were more likely to test positive for an STD (adjusted odds ratio (AOR) = 2.9; P = 0.0001). Adolescents who reported unprotected vaginal sex relative to those reporting protected vaginal sex also had greater odds of testing positive for an STD (AOR = 1.5; P = 0.0001). Prospective findings suggest that having multiple sex partners and engaging in unprotected vaginal sex both remain significant risk factors for STD acquisition among African American adolescent women. STD prevention programmmes need to target both risk factors to achieve optimal risk-reduction effectiveness.