New Delhi: The administration of single booster dose of hepatitis B vaccine (HBV) after 5 years of primary immunization is sufficient for children with beta-thalassemia major, finds a recent study in the journal Indian Pediatrics.
Thalassemia children are particularly vulnerable to hepatitis B infection taking into account multiple transfusions in addition to immunological derangements.
A few studies have shown these children to have immune dysfunction, especially cell mediated immunity, possibly due to iron overload. On the contrary, few studies have shown these children to have active humoral immune response due to repeated antigenic stimulation. The long term seroprotection after HBV reportedly varies from 13-80% in different studies and the need for booster doses remains controversial.
Sunil Gomber, Department of Pediatrics, GB Pant Hospital; New Delhi, India, and colleagues aimed to determine anti-HBs antibody levels in multi-transfused children with betathalassemia major who had received primary hepatitis B vaccination ≥5 years ago, and to document their antibody response to a booster dose of HBV.
The study included 85 Indian children each of beta-thalassemia major and age-matched healthy controls who had completed primary hepatitis B vaccination ≥5 years ago. The researchers assessed the participants for anti-HBs titres. Following this, patients with beta-thalassemia major who were seronegative (titres<10 mIU/mL) were administered a single booster dose of HBV. CD4 counts, serum levels of IL-2 and IFN-γ, and anti-HBs titres were evaluated at baseline and following booster dose of vaccine.
Key findings of the study include:
Seroprotection rates for hepatitis B after an average (SD) duration of 10.8 (3.8) years of completion of primary immunization were significantly higher among children with beta thalassemia major compared to healthy controls (72.9% vs. 52.9%).
All the 23 seronegative children with beta-thalassemia major achieved seroprotection after a single booster dose of hepatitis B vaccine.
"A single booster dose of hepatitis B vaccine after 5 years of primary immunization is adequate to provide seroprotection to multi-transfused children with beta-thalassemia major," wrote the authors.
"Based on our findings and considering the increased risk of hepatitis B in children with beta-thalassemia major, we suggest regular assessment of anti-HBs titres following primary hepatitis B vaccination and recommend administration of a booster dose whenever indicated at the earliest," they concluded.
The study titled, "Requirement of a Booster Dose of Hepatitis B Vaccine in Children With Thalassemia After 5 Years of Primary Vaccination: A Prospective Study," is published in the journal Indian Pediatrics.
DOI: https://indianpediatrics.net/mar2021/237.pdf