Adherence and efficacy of the 0 − 7 − 21-day versus the 0 − 1 − 6-month hepatitis B vaccination schedules among people who use drugs: a two-year randomized controlled trial

To compare the adherence and efficacy between the 0 − 7 − 21-day and the 0 − 1 − 6-month hepatitis B virus (HBV) vaccination schedules among people who use drugs (PWUD) in China. A randomized controlled trial was conducted in 1261 HBV-susceptible PWUD from compulsory isolated detoxification centers (CIDCs) and methadone maintenance treatment (MMT) clinics in Xi’an. A 20 µg per-dose vaccine was used. HBV surface antibody (anti-HBs), surface antigen, and core antibody were tested at months 7, 15, and 22 after the first dose. Third-dose coverage was significantly higher in the 0 − 7 − 21-day group (74.40%) than in the 0 − 1 − 6-month group (51.58%, p < 0.001), mainly driven by participants from CIDCs (77.75% vs. 45.69%). Anti-HBs positive rates at months 7, 15, and 22 among participants who completed all three doses were significantly higher for the 0 − 1 − 6-month schedule (90.71%, 76.82%, and 67.35%) than for the 0 − 7 − 21-day schedule (74.23%, 49.40%, and 40.95%; all p < 0.001). HBV infection incidence was similar between schedules, but significantly different between vaccinees and non-vaccinees (p = 0.018). The 0 − 7 − 21-day schedule substantially enhances three-dose completion in PWUD, but induces a notably weaker anti-HBs response and persistence. Schedules should be selected based on the management models for PWUD and their individual characteristics. Chinese Clinical Trial Registry (ChiCTR1900022403).