Hepatitis B Vaccination in Children With Ongoing Cancer Treatment: A Safety and Efficacy Study of Super-Accelerated Vaccination Scheme

Objective: Children with cancer have an increased risk for hepatitis B virus (HBV) infections due to chemotherapy-induced secondary immunodeficiency and frequent blood transfusions. The aim of this study is to evaluate the efficacy and safety of hepatitis B vaccination during the intensive induction chemotherapy in children with cancer found to be seronegative for hepatitis B on admission. Materials and Methods: Children newly diagnosed with cancer were evaluated for the presence of hepatitis B surface antigen (HBsAg) and antibody on admission. The children negative for both were included in the study. A super-accelerated vaccination scheme (3 booster doses at days 1-5, 8-12, and 28-33) was administered to these seronegative children concurrently with induction chemotherapy. Antibody response was checked 4-8 weeks after the last vaccination and 6 months after the end of the treatment. Results: Eleven out of 122 children were seronegative for hepatitis B on admission (9%). Acute lymphoblastic leukemia, lymphoma, and solid tumors were diagnosed in 5, 4, and 2 children, respectively. Complete seroconversion was achieved in 4-8 weeks after the last vaccination with high titers of anti-HBs antibody, and all patients remained antibody-positive until 6 months after the completion of chemotherapy. Conclusion: The risk of transfusion-related infections increases with a number of transfused products and donor exposures, and it is more significant for immunosuppressed children with hematologic and oncologic malignancies. Hepatitis B vaccination could safely be applied with brisk and sustained responses in this vulnerable population, based on the local epidemiological data.