Age-Related Differences in Past or Present Hepatitis C Virus Infection Among People Who Inject Drugs: National Human Immunodeficiency Virus Behavioral Surveillance, 8 US Cities, 2015

BACKGROUND: Historically, older people who inject drugs (PWID) have had the highest hepatitis C virus (HCV) burden; however, young PWID now account for recent increases. We assessed factors associated with past or present HCV infection (HCV antibody [anti-HCV] positive) among young (≤35 years) and older (>35 years) PWID. METHODS: We calculated adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) to examine sociodemographic and past 12-month injection behaviors associated with HCV infection. RESULTS: Of 4094 PWID, 55.2% were anti-HCV positive. Among young PWID, anti-HCV prevalence was 42.1% and associated with ≤high school diploma/General Education Development diploma (GED) (aPR, 1.17 [95% CI, 1.03-1.33]), receptive syringe sharing (aPR, 1.37 [95% CI, 1.21-1.56]), sharing injection equipment (aPR, 1.16 [95% CI, 1.01-1.35]), arrest history (aPR, 1.14 [95% CI, 1.02-1.29]), and injecting speedball (aPR, 1.37 [95% CI, 1.16-1.61]). Among older PWID, anti-HCV prevalence was 62.2% and associated with ≤high school diploma/GED (aPR, 1.08 [95% CI, 1.02-1.15]), sharing injection equipment (aPR, 1.08 [95% CI, 1.02-1.15]), high injection frequency (aPR, 1.16 [95% CI, 1.01-1.34]), and injecting speedball (aPR, 1.09 [95% CI, 1.01-1.16]). CONCLUSIONS: Anti-HCV prevalence is high among PWID and varies with age. Scaling up direct-acting antiviral treatment, syringe service programs, and medication-assisted therapy is critical to mitigating transmission risk and infection burden.