Significant reduction in Hepatitis B virus infections following 32 years of universal Hepatitis B vaccination as part of EPI, Thailand.

This study aimed to evaluate the impact of Thailand's hepatitis B virus (HBV) National Program Immunization (NPI), 32 years post-implementation, on infection rates and immunity in various age groups. A cross-sectional study involved 6,068 participants aged 6 months to 80 years from four regions in Thailand. Blood samples were tested for HBsAg, anti-HBs, and anti-HBc using a chemiluminescent immunoassay.