HIV-1 transmission dynamics among people who inject drugs on the US/Mexico border during the COVID-19 pandemic: a prosepective cohort study

Britt Skaathun; Steffanie A Strathdee; Cho-Hee Shrader; Carrie L Nacht; Annick Borquez; Irina Artamonova; Alicia Harvey-Vera; Carlos F Vera; Gudelia Rangel; Caroline Ignacio; Brendon Woodworth; Antoine Chaillon; Tetyana I Vasylyeva

doi:10.1016/j.lana.2024.100751

HIV-1 transmission dynamics among people who inject drugs on the US/Mexico border during the COVID-19 pandemic: a prosepective cohort study

Lancet Reg Health Am. 2024 Apr 30:33:100751. doi: 10.1016/j.lana.2024.100751. eCollection 2024 May.

Authors

Affiliations

¹ Division of Infectious Diseases and Global Public Health, University of California, San Diego, 9500 Gilman Dr, La Jolla, CA 92093, United States.
² Department of Epidemiology, Columbia University, 116th and Broadway, New York, NY 10027, United States.
³ Herbert Wertheim School of Public Health and Human Longevity Science, University of California San Diego, 9500 Gilman Dr, La Jolla, CA 92093, United States.
⁴ U.S.-Mexico Border Health Commission, Paseo del Centenario 10851, Zona Urbana Rio Tijuana, Tijuana, BC 22320, Mexico.
⁵ El Colegio de la Frontera Norte, Carretera Escenica Tijuana-Ensenada Toll Boot Escenica Tijuana-Ensenada Sn San Antonio del Mar, Tijuana, BC 22560, Mexico.
⁶ Department of Population Health and Disease Prevention, University of California Irvine, Irvine, CA 92617, United States.

Abstract

Background: We examined HIV prevalence and transmission dynamics among people who inject drugs in the U.S./Mexico border region during the COVID-19 pandemic.

Methods: People who inject drugs aged ≥18 years from 3 groups were recruited: people who inject drugs who live in San Diego (SD) and engaged in cross-border drug use in Tijuana, Mexico (SD CBDUs), and people who inject drugs in SD and Tijuana (TJ) who did not engage in cross-border drug use (NCBDUs). We computed HIV prevalence at baseline and bivariate incidence-density rates (IR) at 18-month follow-up. Bayesian phylogenetic analysis was used to identify local transmission clusters, estimate their age, and effective reproductive number (Re) over time within the clusters.

Findings: At baseline (n = 612), 26% of participants were female, 9% engaged in sex work, and HIV prevalence was 8% (4% SD CBDU, 4% SD NCBDU, 16% TJ NCBDU). Nine HIV seroconversions occurred over 18 months, IR: 1.357 per 100 person-years (95% CI: 0.470, 2.243); 7 in TJ NCBDU and 2 in SD CBDU. Out of 16 identified phylogenetic clusters, 9 (56%) had sequences from both the U.S. and Mexico (mixed-country). The age of three youngest mixed-country dyads (2018-2021) overlapped with the COVID-related US-Mexico border closure in 2020. One large mixed-country cluster (N = 15) continued to grow during the border closure (Re = 4.8, 95% Highest Posterior Density (HPD) 1.5-9.1) with 47% engaging in sex work.

Interpretation: Amidst the COVID-19 pandemic and the border closure, cross-border HIV clusters grew. Efforts to end the HIV epidemic in the U.S. should take into account cross-border HIV-1 transmission from Tijuana. Mobile harm reduction services and coordination with municipal HIV programs to initiate anti-retroviral therapy and pre-exposure prophylaxisis are needed to reduce transmission.

Funding: This research was supported by the James B. Pendleton Charitable Trust and the San Diego Center for AIDS Research.

Keywords: Cross-border transmission; HIV; People who inject drugs; Phylodynamics; Tijuana.

Abstract

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