Abstract
OBJECTIVE: To assess the immunization efficacy and incidence of adverse reactions after hepatitis B vaccination in children with thalassemia based on data from real-world studies. METHODS: A total of 625 children were recruited into this cross-sectional study. Subgroup analyses of different thalassemia types were performed using binary logistic regression, the factors affecting HBsAb levels were identified using multiple linear regression, and the dose-response relationship between the duration of immunization and seroconversion was explored using the restricted cubic spline (RCS) model to further assess the protective duration of the hepatitis B vaccine. RESULTS: HBsAb positivity in enrolled children was 87.3% in the thalassemia group and 81.4% in the control group. Multifactorial analysis revealed that the duration of immunization, age at completion of vaccination, and whether the first dose was delayed were significant factors influencing HBsAb levels in children (P < 0.05). The threshold for HBsAb positivity may be reached when the immunization duration reaches approximately 30 months. A subgroup analysis revealed that the HBsAb positivity rate was lower in children with β-thalassemia minor compared to those with α-thalassemia minor (P = 0.001, 95% CI: 0.097 ∼ 0.536). Adverse reactions after hepatitis B vaccination were dominated by general reactions, with a statistically significant difference in injection-site redness and swelling between the thalassemia and control groups (P < 0.05). CONCLUSIONS: The immunization response to the hepatitis B vaccine in children with thalassemia minor was comparable to healthy children, with no abnormal adverse effects seen.