Impact of Serum 25(OH) D Levels on Immune Responses to Hepatitis B Virus Vaccination in Healthy Adults: A Cross-Sectional Study in Mane and Samalghan City, Iran

Backgrounds: Several studies have elucidated vitamin D as an important immunomodulatory factor regulating immune responses to different viral infections and vaccines. This study aimed to evaluate the impact of 25(OH) D serum levels on immune responses to hepatitis B virus (HBV) vaccine. Materials Methods: This study was conducted on 134 healthy individuals aged 18-35 years, referring to health centers for HBV vaccination in Mane and Samalghan city in North Khorasan, Iran from June to September 2021. Demographic data were collected through a questionnaire. Serum 25(OH) D levels were analyzed using commercial sandwich ELISA kits. Anti-hepatitis B surface antibody (anti-HBsAb) levels were determined in blood samples 4-6 weeks post-vaccination. Findings: The prevalence of vitamin D deficiency and insufficiency among the participants was 46.3 was 34.3%, respectively. The level of 25(OH) D was insignificantly higher in women than in men. There was no significant association between serum 25(OH) D levels and participants’ ethnicities and BMI ranges. Anti-HBsAb titer was significantly higher in participants with sufficient vitamin D levels compared to those with insufficient and deficient levels (1835 ± 252.55 vs. 1129 ± 120.7 and 1363 ± 0.125 ng/ml). Serum anti-HBsAb levels post HBV vaccination were significantly higher in women and younger individuals than in men and older individuals, respectively. Conclusion: This study findings suggest that participants with different serum vitamin D levels produce seroprotective antibody titers post HBV vaccination, while those with sufficient vitamin D levels may produce higher titers against HBV vaccine.