Prevalence of blood-borne viral infections and HBV vaccination coverage among people with recent injecting drug use in Oslo, 2002-2024.

BACKGROUND & AIMS: We assessed changes in the prevalence of HCV, HBV, HIV and HBV vaccination coverage among people with recent injecting drug use in Oslo between 2002 and 2024. METHODS: We used data from eight cross-sectional studies among PWID in Oslo in 2002, 2012, 2015, 2018 and 2021-2024. Participants (≥18 years, injected drugs within the past four weeks) completed venipuncture and a questionnaire. Outcomes were detectable HCV RNA, HIV Ag/Ab, HBsAg, and HBV vaccination coverage, defined as anti-HBs ≥10 IU/L among anti-HBc negative individuals. Factors were analysed using generalised estimating equations. RESULTS: We included 1689 participants. HCV RNA prevalence decreased from 50.2% (95% CI 44.4-55.9) in 2002 (153/305) to 6.3% (95% CI 3.5-10.4) in 2024 (14/221). Detectable HCV RNA was associated with year of participation (2024 vs 2002; aOR 0.06; 95% CI 0.03-0.11), age (aOR 1.30 per 10-year increment; 95% CI 1.14-1.49) and daily injecting drug use (aOR 1.33; 95% CI 1.01-1.74). The prevalence of HBsAg and HIV remained low (<3.3%) throughout. In 2021-2024, 40.0% (95% CI 35.3-44.8; 170/425) of those not exposed to HBV were vaccinated. HBV vaccination was associated with recent use of a drug consumption room (aOR 1.33; 95% CI 1.02-1.72). CONCLUSION: HCV RNA prevalence among people with recent injecting drug use in Oslo decreased significantly between 2002 and 2024, while the prevalence of HIV and HBsAg remained low and stable. Future efforts should focus on identifying and treating the remaining population infected with HCV, increasing HBV vaccination uptake, and maintaining low HIV prevalence.