Reductions in HIV/STI Incidence and Sharing of Injection Equipment among Female Sex Workers Who Inject Drugs: Results from a Randomized Controlled Trial

<div><p>Background</p><p>We evaluated brief combination interventions to simultaneously reduce sexual and injection risks among female sex workers who inject drugs (FSW-IDUs) in Tijuana and Ciudad Juarez, Mexico during 2008–2010, when harm reduction coverage was expanding rapidly in Tijuana, but less so in Juarez.</p><p>Methods</p><p>FSW-IDUs ≥18 years reporting sharing injection equipment and unprotected sex with clients within the last month participated in a randomized factorial trial comparing four brief, single-session conditions combining either an interactive or didactic version of a sexual risk intervention to promote safer sex in the context of drug use, and an injection risk intervention to reduce sharing of needles/injection paraphernalia. Women underwent quarterly interviews and testing for HIV, syphilis, gonorrhea, <i>Chlamydia</i> and <i>Trichomonas,</i> blinding interviewers and assessors to assignment. Poisson regression with robust variance estimation and repeated measures ordinal logistic regression examined effects on combined HIV/STI incidence and receptive needle sharing frequency.</p><p>Findings</p><p>Of 584 initially HIV-negative FSW-IDUs, retention was ≥90%. After 12 months, HIV/STI incidence decreased >50% in the interactive vs. didactic sex intervention (Tijuana:AdjRR:0.38,95% CI:0.16–0.89; Juarez: AdjRR:0.44,95% CI:0.19–0.99). In Juarez, women receiving interactive vs. didactic injection risk interventions decreased receptive needle-sharing by 85% vs. 71%, respectively (p = 0.04); in Tijuana, receptive needle sharing declined by 95%, but was similar in active versus didactic groups. Tijuana women reported significant increases in access to syringes and condoms, but Juarez women did not.</p><p>Interpretation</p><p>After 12 months in both cities, the interactive sexual risk intervention significantly reduced HIV/STI incidence. Expanding free access to sterile syringes coupled with brief, didactic education on safer injection was necessary and sufficient for achieving robust, sustained injection risk reductions in Tijuana. In the absence of expanding syringe access in Juarez, the injection risk intervention achieved significant, albeit more modest reductions, suggesting that community-level interventions incorporating harm reduction are more powerful than individual-level interventions.</p><p>Trial Registration</p><p>clinicaltrials.gov <a href="http://www.clinicaltrials.gov/ct2/show/NCT00840658?term=NCT00840658&rank=1" target="_blank">NCT00840658</a></p></div

Descriptive Statistics of Participants by Intervention Group at Baseline, by Study Site (n = 584).

<p>Descriptive Statistics of Participants by Intervention Group at Baseline, by Study Site (n = 584).</p

HIV/STI incidence density over 12 months: Overall, by intervention group and site.

<p>HIV/STI incidence density over 12 months: Overall, by intervention group and site.</p

Reported Number of Syringes Exchanged and Prevenkits* Distributed in Tijuana and Ciudad Juarez: 2007–2011.

<p>*Safer injection kits including sterile cotton, cooker and water.</p

Intervention effects on HIV/STI incidence after 12 months: Tijuana^*.

<p>Intervention effects on HIV/STI incidence after 12 months: Tijuana^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065812#nt108" target="_blank">*</a>}.</p

Intervention effect on 12 months HIV/any STI incidence rate: Ciudad Juarez^*.

<p>Intervention effect on 12 months HIV/any STI incidence rate: Ciudad Juarez^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065812#nt109" target="_blank">*</a>}.</p

Changes in Proportional Log Odds of Receptive Needle Sharing among Participants in Tijuana and Ciudad Juarez Receiving Interactive or Didactic Injection Risk Interventions.

<p>Changes in Proportional Log Odds of Receptive Needle Sharing among Participants in Tijuana and Ciudad Juarez Receiving Interactive or Didactic Injection Risk Interventions.</p

Cost-effectiveness acceptability curve for the combined interactive safer sex/Safer injection intervention for Ciudad Juarez.

<p>Cost-effectiveness acceptability curve for the combined interactive safer sex/Safer injection intervention for Ciudad Juarez.</p

Cost-effectiveness acceptability curve for the combined interactive safer sex/ didactic safer injection intervention in Cd. Juarez.

<p>Cost-effectiveness acceptability curve for the combined interactive safer sex/ didactic safer injection intervention in Cd. Juarez.</p

Costs associated with the Mujer Mas Segura intervention.

<p>Costs associated with the Mujer Mas Segura intervention.</p