Retrospective analysis of Hepatitis B seroprevalence and vaccination coverage in South India: Bridging laboratory evidence with literature trends.

Hepatitis B virus (HBV) continues to pose a substantial public health issue in India, classified as an intermediate endemic area. Despite the decline in HBV incidence among younger groups due to childhood immunization, adult seroprevalence and age-specific trends need more assessment. The objective is to evaluate the temporal and age-specific trends of HBV seropositivity over six years (January 2018- December 2023) in a tertiary care hospital in South India and to identify high-risk populations to inform vaccination strategies. A retrospective analysis of 78,818 serum samples tested for hepatitis B surface antigen (HBsAg) was performed using rapid immunochromatographic tests and chemiluminescent microparticle immunoassay (CMIA). During the six-year period, 1421 individuals tested seropositive for HBsAg. Demographic data and vaccination history were obtained, and statistical analysis was conducted to assess year-wise and age-specific trends. Seropositivity decreased from 2.31 % in 2018 to 1.47 % in 2023 (p < 0.001). The greatest positive was seen in the 51-60 age group (25.89 %), followed by the 41-50 (21.9 %) and 31-40 years (15.8 %) cohorts, indicating an elevated risk for these persons. The lowest seropositivity occurred in individuals ≤20 years, demonstrating the influence of early-life immunization. A decline in detection in 2020 corresponded with the COVID-19 pandemic. Vaccination coverage was significantly inadequate among persons aged 31 years and older. These findings emphasize the urgent need for adult-focused HBV vaccination and screening initiatives.