neonatal vaccination and hbv prevalence: evidence from esfandiar village, iran

Background and objectives: hepatitis b virus (hbv) remains a major public health challenge, particularly in hyperendemic regions. this study assessed the effectiveness of iran's national hbv vaccination program in esfandiar village, south khorasan province, where hbv prevalence substantially exceeds the national average. we compared hepatitis b surface antigen (hbsag) prevalence between cohorts born before and after implementation of the universal vaccination program in 1993.materials and methods: we conducted a cross-sectional seroprevalence study encompassing both unvaccinated individuals (born before 1993) and vaccinated individuals (born 1993 onwards) in esfandiar village. serum samples were analyzed for hbsag, hepatitis b e antigen (hbeag), and hepatitis b core antibody (hbcab) using enzyme-linked immunosorbent assay (elisa).results: hbsag prevalence was markedly higher among unvaccinated individuals (22.56%, 132/585) compared to vaccinated individuals (1.19%, 3/252), yielding a vaccine effectiveness of 94.74%. among vaccinated children, 54% maintained protective antibody titers (>10 miu/ml), with highest levels observed in children born to hbsag-positive mothers. conversely, 46% of vaccinated children demonstrated suboptimal antibody titers (<10 miu/ml), predominantly among those born to hbsag-negative mothers. notably, all three hbsag-positive vaccinated children were born to mothers with concurrent hbsag and hbeag positivity.conclusion: the national hbv vaccination program demonstrates remarkable effectiveness in reducing hbsag prevalence, underscoring the critical importance of universal neonatal immunization in endemic settings. enhanced preventive strategies, including hepatitis b immunoglobulin (hbig) administration to infants of hbeag-positive mothers, could further optimize protection. sustained surveillance and rigorous adherence to vaccination protocols remain essential for achieving comprehensive hbv control.