Addict Sci Clin Pract. 2023 Jan 3;18(1):2. doi: 10.1186/s13722-022-00358-7.
BACKGROUND: Among people who inject drugs (PWID), obtaining syringes via syringe services programs (SSPs) and pharmacies reduces injection sharing practices associated with hepatitis C virus (HCV). Whether indirect use of SSPs via secondary exchange confers a similar benefit remains unknown, particularly in rural settings. We compared HCV serostatus and injection sharing practices by primary syringe source among a sample of rural PWID.
METHODS: Data are from a cross-sectional study of adults who use drugs recruited from eleven rural counties in New Hampshire, Vermont, and Massachusetts using respondent-driven sampling (2018-2019). Study staff performed HCV antibody testing. An audio computer-assisted self-interview assessed sociodemographic characteristics, past 30-day injection practices, and past 30-day primary syringe source. Primary syringe source was classified as direct SSP, pharmacy, indirect SSP (secondary exchange), or “other” (friend/acquaintance, street seller, partner/relative, found them). Mixed effects modified Poisson models assessed the association of primary syringe source with HCV seroprevalence and injection sharing practices.
RESULTS: Among 397 PWID, the most common primary syringe source was “other” (33%), then pharmacies (27%), SSPs (22%), and secondary exchange (18%). In multivariable models, compared with those obtaining most syringes from “other” sources, those obtaining most syringes from pharmacies had a lower HCV seroprevalence [adjusted prevalence ratio (APR):0.85, 95% confidence interval (CI) 0.73-0.9985]; however, the upper bound of the 95% CI was close to 1.0. Compared with those obtaining most syringes from other sources, PWID obtaining most syringes directly from SSPs or pharmacies were less likely to report borrowing used syringes [APR(SSP):0.60, 95% CI 0.43-0.85 and APR(Pharmacies):0.70, 95% CI 0.52-0.93], borrowing used injection equipment [APR(SSP):0.59, 95% CI 0.50-0.69 and APR (Pharmacies):0.81, 95% CI 0.68-0.98], and backloading [APR(SSP):0.65, 95% CI 0.48-0.88 and APR(Pharmacies):0.78, 95% CI 0.67-0.91]. Potential inverse associations between obtaining most syringes via secondary exchange and injection sharing practices did not reach the threshold for statistical significance.
CONCLUSIONS: PWID in rural New England largely relied on informal syringe sources (i.e., secondary exchange or sources besides SSPs/pharmacies). Those obtaining most syringes from an SSP or pharmacy were less likely to share injection equipment/syringes and had a lower HCV seroprevalence, which suggests using these sources reduces the risk of new HCV infections or serves as proxy for past injection behavior.