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Identification of a Syndemic of Blood-Borne Disease Transmission and Injection Drug Use Initiation at the US–Mexico Border

Rafful, Claudia, PhD*,†; Jain, Sonia, PhD; Sun, Xiaoying, MS; Strathdee, Steffanie A., PhD*; Garfein, Richard S., PhD*; Cuevas-Mota, Jazmine, MPH*; Magis-Rodríguez, Carlos, PhD§; Smith, Laramie R., PhD*; Werb, Dan, PhD*,†

JAIDS Journal of Acquired Immune Deficiency Syndromes: December 15, 2018 - Volume 79 - Issue 5 - p 559–565
doi: 10.1097/QAI.0000000000001858

Background: Efforts to prevent injection drug use (IDU) are increasingly focused on the role that people who inject drugs (PWID) play in the assistance with injection initiation. We studied the association between recent (ie, past 6 months) injection-related HIV risk behaviors and injection initiation assistance into IDU among PWID in the US–Mexico border region.

Setting: Preventing Injecting by Modifying Existing Responses (PRIMER) is a multicohort study assessing social and structural factors related to injection initiation assistance. This analysis included data collected since 2014 from 2 participating cohorts in San Diego and Tijuana.

Methods: Participants were 18 years and older and reported IDU within the month before study enrollment. Logistic regression analyses were conducted to assess the association between recent injection-related HIV risk behaviors (eg, distributive/receptive syringe sharing, dividing drugs in a syringe, and paraphernalia sharing) and recent injection initiation assistance.

Results: Among 892 participants, 41 (4.6%) reported recently providing injection initiation assistance. In multivariable analysis adjusting for potential confounders, reporting a higher number of injection-related risk behaviors was associated with an increased odds of recently assisting others with injection initiation (adjusted odds ratio per risk behavior: 1.3; 95% confidence interval: 1.0 to 1.6, P = 0.04).

Conclusions: PWID who recently engaged in one or more injection-related HIV risk behavior were more likely to assist others in injection initiation. These results stress the syndemic of injection initiation and risk behaviors, which indicates that prevention of injection-related HIV risk behaviors might also reduce the incidence of injection initiation.

*Division of Infectious Diseases and Global Public Health, University of California San Diego, La Jolla, CA;

Centre for Urban Health Solutions, St. Michael's Hospital, Toronto, Ontario, Canada;

Department of Family Medicine and Public Health, Biostatistics Research Center, University of California San Diego, La Jolla, CA; and

§Centro Nacional para la Prevención y el Control del VIH y el SIDA (CENSIDA), Anzures, Mexico City, Mexico.

Correspondence to: Dan Werb, PhD, Division of Global Public Health, University of California School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0507 (e-mail:

D.W. was supported by a grant to the PRIMER study from the National Institute on Drug Abuse (NIDA; DP2-DA040256-01) and by the Canadian Institutes of Health Research through a New Investigator Award. El Cuete IV was supported by NIDA (R37 DA019829). STAHR II was supported by NIDA R01DA031074. C.R. was supported by a UC-MEXUS/CONACyT scholarship 209407/313533, and the UC MEXUS Dissertation Grant DI 15-42 and by the Canadian Institutes of Health Research through a Postdoctoral Fellowship. L.S. was supported by the K01-DA039767.

The authors have no funding or conflicts of interest to disclose.

All authors had full access to all data and have read and approved the text as submitted to JAIDS. C.R. drafted the manuscript; S.J. and S.S. performed methodological analyses. D.W., L.R.S., C.M.-R., J.C.-M., R.S.G., and S.A.S. contributed to manuscript revisions. The authors alone are responsible for the content and writing of this article.

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Received March 13, 2018

Accepted August 20, 2018

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