RESUMEN
Introduction: Hepatitis B virus (HBV) infection is a global health problem. Anti-hepatitis B surface antigen (HBsAg) levels increase along with vitamin D levels in adults. However, few studies have examined this relationship in adolescents. Few studies have examined the relationship between vitamin D and HBsAg antibody levels, especially in Indonesia. Methods: This cross-sectional study examined vitamin D and anti-HBsAg levels before and after hepatitis B immunisation. All subjects blood was taken to check for vitamin D level. This study was part of the Safety and Preliminary of Immunogenicity Following Recombinant Hepatitis B (Bio Farma) Vaccine in Adults and Children Phase I trial. Results: This study found that 25-hydroxyvitamin D [25(OH)D] status was primarily deficient based on endocrine criteria. The children's hepatitis B antibody response was mostly <10 mIU/mL before and ≥10 mIU/mL after vaccination. There was a relationship between sex and 25(OH)D status, with median 25(OH)D levels higher in females (18.2 ng/mL) than in males (9.8 ng/mL). However, the relationship between vitamin 25(OH)D status and anti-HBsAg levels pre- and post-vaccination was not significant. Discussion: However, some research found that vitamin D supplementation after immunisation did not impact vaccine response, several studies have reported that vitamin D can decrease HBV replication through various mechanisms, including reducing viral transcription and interfering with viral protein synthesis. Conclusion: There was no relationship between 25(OH)D status and anti-HBsAg levels. Further research is needed to elucidate the underlying mechanisms and establish optimal treatment strategies.