Background: HBsAg vaccination might help to control HBV replication following nucleos(t)ide analog therapy. We tested HBsAg vaccine in a patient who developed lamivudine resistance.
Patient and results: An HBeAg negative HBV chronically-infected patient developed HBsAg seroconversion after 3 years of treatment by lamivudine. However, the control of HBV replication was transient and HBV DNA could be detected in the serum one year after lamivudine was stopped. Concurrently, the anti-HBs antibodies (HBsAb) titre had decreased from more than 100 IU/L to 23 IU/L. Due to the presence of rtM204V resistance mutation, lamivudine was not reintroduced and the patient was treated by HBsAg vaccination. After three injections, HBV DNA was no more detectable and the HBsAb titre reached more than 200 IU/L.
Conclusion: This observation suggests that a regular follow up of patients presenting HBsAg seroconversion following lamivudine therapy is necessary. In these patients, a low titre of HBsAb may not prevent from lamivudine-resistant HBV reactivation. Evaluation of HBsAg vaccination to maintain HBsAb at a high titre in these patients deserves further studies.