Susceptibility to Hepatitis B Virus Infection Among People Who Inject Drugs in Montreal, Canada

Introduction

People who inject drugs are at elevated risk of hepatitis B virus (HBV) infection, which is preventable by vaccination. We examined susceptibility to HBV infection among a sample of people who inject drugs and live in Montreal, Canada.

Methods

Data were obtained from HEPCO, a prospective cohort study of people who had recently (within the past six months) injected drugs, between November 2022 and March 2024. The absence of hepatitis B surface antibody indicated susceptibility to HBV infection. These results were compared to self-report immune status. Logistic regression was used to identify factors associated with HBV susceptibility.

Results

Overall, 28.1% (108/384) of participants were susceptible to HBV infection. Over half (60.2%, 231/384) of participants correctly reported their immune status. Individuals born in Canada prior to the introduction of universal childhood vaccination programs had higher odds of susceptibility to HBV infection (adjusted odds ratio: 2.63, 95% confidence interval: 1.34–5.61), while those in opioid agonist treatment (0.60, 0.37–0.98) and with a history of hepatitis C infection (0.51, 0.32–0.83) had lower odds of HBV susceptibility.

Discussion and Conclusions

An important minority of people who inject drugs in Montreal remain susceptible to HBV infection. Moderate concordance between self-report and serological results indicates that serology or vaccine registry information should continue to be used to inform immunisation provision. People who inject drugs who were born prior to childhood vaccination programs and/or are not in opioid agonist treatment are subpopulations who require targeted interventions to increase vaccination coverage.