Seroprotection Status Against Hepatitis B among Children on Bawean Island, Indonesia

Hepatitis B virus (HBV) remains a major global public health concern, particularly in developing regions. Vaccination significantly reduces infection rates, but seroprotection may decline over time, necessitating periodic evaluation. This study evaluated the seroprotection rates against hepatitis B and the prevalence of HBV infection among children on Bawean Island, Indonesia. A cross-sectional study was conducted involving 90 children aged 3-15 years from various villages on Bawean Island. Blood samples were collected to determine hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) levels using an Electrochemiluminescence Immunoassay (ECLIA). Seroprotection was defined as anti-HBs titers ≥10 mIU/mL. Statistical analyses were performed using SPSS Version 25, utilizing the chi-square test for categorical variables and the Spearman correlation test for continuous data. None of the subjects were reactive for HBsAg (0%). The overall anti-HBs seroprotection rate among the children was 67.8 %. There was a significant difference between seroprotection status and age (p<0.001). However, no significant difference was found between seroprotection status and sex (p=0.259) or basic immunization history (p=0.627). A significant negative correlation was found between age and Anti-HBs titers (r=-0.404, p<0.001). This study demonstrates the presence of seroprotection among children on Bawean Island. The significant age-dependent decline in anti-HBs titers highlights the potential need for a booster vaccination strategy in this remote island population to ensure long-term immunity.