Characterizing hepatitis C virus transmission dynamics using molecular phylogenetic-based methods

Hanover and Frankfurt, up to 71.6% reported consumption of crack, in Leipzig 66.9% indicated consumption of methamphetamine. History of incarceration was reported by 72.8–85.8%, and 17.7–39.8% of these had injected drugs in prison. 54.6–88.1% have ever been in opioid substitution therapy (OST). HCV-seroprevalence was 42.3–75.0%, with 23.1–54.0% of viremic infections. HBV-prevalence (HBV-DNA or anti-HBc) was 4.6–33.0%, and anti-HBs as marker for vaccination was 15.1–52.4%. The proportion of participants ever tested for HCV was 70.3–95.9%. We diagnosed 9.5–28.8% of viremic HCV-infections among never positive-tested participants in the respective cities. Unsafe use behaviour like sharing needles, syringes or other paraphernalia like spoons, filters or water was indicated by 36–48%. We identified gaps in knowledge of HCV transmission, HBV vaccination and HCV treatment options. Targeted counselling was accepted by 29.8–79.8%. CONCLUSION: High HCV prevalence and low prevalence of HBV vaccination despite official national recommendations to provide HBV vaccination to all PWID indicate the need for intensified prevention strategies, scale-up of targeted vaccination and of antiviral treatment, above all of HCV among PWID. Targeted counselling was well accepted and should be regularly offered in low-threshold drug services. Incarceration and regular contact with the medical system during OST should be effectively used for prevention measures, testing, counselling and treatment.