title: Reductions in HIV/STI incidence and sharing of injection equipment among female sex workers who inject drugs: results from a randomized controlled trial.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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, Chlamydia and Trichomonas, 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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
  
  
  BACKGROUND
  clinicaltrials.gov NCT00840658.
authors.affiliation: University of California San Diego, Department of Medicine, La Jolla, California, United States of America. sstrathdee@ucsd.edu
authors.forename: Steffanie A
authors.initials: SA
authors.lastname: Strathdee
authors.forename: Daniela
authors.initials: D
authors.lastname: Abramovitz
authors.forename: Remedios
authors.initials: R
authors.lastname: Lozada
authors.forename: Gustavo
authors.initials: G
authors.lastname: Martinez
authors.forename: Maria Gudelia
authors.initials: MG
authors.lastname: Rangel
authors.forename: Alicia
authors.initials: A
authors.lastname: Vera
authors.forename: Hugo
authors.initials: H
authors.lastname: Staines
authors.forename: Carlos
authors.initials: C
authors.lastname: Magis-Rodriguez
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Patterson
mesh_terms: D000328:Adult; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D008800:Mexico / Q000453:epidemiology; D016485:Needle Sharing; D012307:Risk Factors; D060386:Sex Workers; D012749:Sexually Transmitted Diseases / Q000453:epidemiology* / Q000209:etiology; D015819:Substance Abuse, Intravenous; D011795:Surveys and Questionnaires