Sufficiency of Hepatitis B Vaccine Single Booster Dose to Seroconverse Immunity to HBV Among Health Workers

Objective: To 1) determine the proportion of health workers with prior hepatitis B vaccination history who developed immunity after single booster dose of hepatitis B vaccine, 2) evaluate positive predictive value of self-reported hepatitis B vaccination history in predicting immune response among health workers at a university hospital in Thailand. Materials and Methods: The present study was a single-arm prospective study. The study population included 157 health workers born after 1992 who tested negative immunity as anti-HBs of less than 10 mIU/mL, at pre-placement examinations between October 2023 and September 2024, with calculated sample size of 113 participants. The research tools included vaccination history questionnaire and existing records from the Occupational Health and Safety Office. Those with prior vaccination history received single dose of recombinant hepatitis B vaccine (rDNA) (Serum Institute of India Pvt. Ltd.), and anti-HBs levels were measured 30 to 40 days after vaccination. Results: Of the 113 participants, 50 had prior hepatitis B vaccination history, and 100% developed immunity after a booster dose. Most received the vaccine during adulthood within last five years. Among the 63 participants with no or uncertain vaccination history, 49 (77.8%) developed immunity, while 14 (22.2%) did not develop immunity after a single dose. A comparison of anti-HBs levels before and after administration of a single dose of hepatitis B vaccine across three groups was done and 1) individuals with a history of prior vaccination (p<0.001), 2) individuals without a history of prior vaccination (p<0.001), and 3) individuals with uncertain vaccination history (p=0.018), demonstrated a significant increase in anti-HBs levels following vaccination. Conclusion: A single hepatitis B vaccine booster induced protective immunity in 100% of initially seronegative health workers who had prior vaccination history. Documented vaccination within five years correlated with stronger immune responses. These findings support booster dose protocols and highlight the necessity of verified vaccination records for optimal immunization strategies.