Post-vaccination immunity against hepatitis B in children with Down syndrome

Relevance. An urgent task of modern medicine is to assess the effectiveness of the immune response to hepatitis B vaccination in children with Down syndrome. Studies show that most children with Down syndrome do not develop sufficient levels of protective antibodies after standard hepatitis B vaccination. Assessing the effectiveness of the immune response will allow for the development of personalized vaccination programs for children with Down syndrome. Objective: to assess the effectiveness of the immune response to hepatitis B vaccination in children with Down syndrome by studying the concentration of specific antibodies in their blood serum and comparing the results with their vaccination status. Materials and methods. A cross-sectional cohort study was performed with the participation of 102 children with Down syndrome aged from 1 to 17 years. The concentration of IgG antibody titers to hepatitis B was analyzed, based on age and vaccination status (full, partial vaccination, no vaccination). Results. 73 (71,6 %) children had completed hepatitis B vaccination among all the subjects. The concentration of hepatitis B antibodies in children with Down syndrome decreases significantly with age, reaching a titer below 10 mIU/ml in most adolescents over 12 years of age. In children with complete vaccination in the 1–5 years group, the geometric mean of antibody titers was 24.5 mIU/ml, in the 6–11 years group, it was 26.7 mIU/ml, while in children aged 12–17 years, the antibody titers were below the protective threshold, with a geometric mean of 2.13 mIU/ml, indicating the need for further revaccination under certain conditions. Correlation analysis revealed a negative relationship between age and antibody levels (r = −0.3205, p = 0.0057). Children with Down syndrome do not have an epidemiological advantage for hepatitis B in “indicator” groups Conclusion. Among children with Down syndrome aged 12 years and older who have received a full course of hepatitis B vaccination, there is a very high percentage of those who do not have a p rotective antibody titer. It is recommended to develop a personalized approach to revaccination and monitor post-vaccination antibodies to maintain an adequate level of protection.