Hepatitis B long-term seroprotection and the response to a challenging dose among vaccinated children in Gharbeya Governorate

Abstract

Objective The aim of the study was to assess the long-term effectiveness of hepatitis B virus (HBV) vaccine and the need for a booster dose among fully vaccinated children during infancy in Gharbeya Governorate. Patients and methods A cross-sectional study was conducted using a multistage random sampling in one city and three villages in Gharbeya Governorate. Face-to-face interview with parents of 762 children was carried out. Blood samples were collected to assess HBV markers using enzyme-linked immunosorbent assay technique. Children having no HBV seroprotection received a challenging booster dose of HBV vaccine to assess their anamnestic response 3 weeks later. Results None of the participants had an evidence of chronic or breakthrough HBV infection, and the seroprotection rate was 57%. On multivariate analysis, the risk of nonseroprotection was found to be significantly higher among children aged from 5 to less than 10, 10 to less than 15, and 15 years and above compared with those aged less than 5 years [adjusted odds ratio (AOR)=3.4, 10.2, and 18.5, respectively], among girls compared to boys (AOR=1.5), and among those living in Kotour and Elsanta villages compared with Tanta city (AOR=1.8). Of the 265 children with nonseroprotective levels, 91.7% developed anamnestic response after a challenging dose. Anamnestic response rate was 100% at age 1 year and decreased to 89% at age 16 years (P>0.05). Conclusion Long-term immunity exists among children who had complete series of hepatitis B vaccination in infancy even in case of reduced or absent anti-hepatitis B over time. The developed high anamnestic response rate signifies the presence of immune memory and indicates no need for a booster dose.