“…Although there is extensive literature on drug use trajectories and transition to injection among people who use drug users worldwide (Ambekar et al, 2019;Baluku, Wamala, & Muhangi, 2019;Bluthenthal, Wenger, Chu, Bourgois, & Kral, 2017;Brecht, Huang, Evans, & Hser, 2008;Horyniak et al, 2015;Hser, 2007;Koozegar, Shahesmaeili, & Noroozi, 2018;Neaigus et al, 2001;Oliveira et al, 2006;Roy et al, 2003;Vidal-Trecan, Varescon-Pousson, & Boissonnas, 2002), in Mexico, the literature is still limited and, in most cases, restricted to PWID who live in Tijuana (Bloom et al, 2021;Fuller et al, 2002;Ben Hamida et al, 2018;Meyers et al, 2021;Mittal et al, 2019;Morris et al, 2012;Rafful et al, 2018;Robertson, Lozada, Pollini, Rangel, & Ojeda, 2012).…”