2364 Case Studies: Hepatitis B Surface Antigen Positive or DNA Detectable After Vaccination?

Abstract

INTRODUCTION: After 1980s, hepatitis B (Hep B) vaccine reduced 80% of the incidence of acute infection. It has not been necessary to check blood work after immunization, but we happened to have two patients who had blood work after Hep B vaccination. CASE DESCRIPTION/METHODS: 1)A 59 years old female, found to be HBsAg positive in the ED when she had GERD and presented with atypical chest pain. In her hepatitis linkage-to-care visit, we found she had her first dose of Hep B vaccine 3 days before her ED visit. We rechecked the blood work one month after her vaccine, and it showed low surface antibody titer and no antigen at all. 2)A 62 years old male was found to have positive isolated total core antibody (anti-HBc) on 4/27/2015 from his physical checkup. Other history included type II DM and insomnia. He received a Hep B booster on 5/21 and repeated blood work on 6/25 found still isolated anti-HBc. Further blood work in August, including Hep B e Ag, e Ab and viral load, verified this patient didn't have an active infection. He finished the three-dose vaccine series. Incidental Hep B panel drawn on 12/23 found detectable DNA (< 20) with negative HBsAg and positive anti-HBs. DISCUSSION: The phenomenon of HBsAg being positive after vaccination is reported in several studies; however, most of them are hemodialysis patients. The surface Ag could be positive for 6 weeks after vaccination. The incidence of positive isolated anti-HBc was found higher in endemic countries than in low prevalence areas. Since the second patient is from China, a hyperendemic area, the possible interpretation of his blood work is either, after many years of recovering from chronic Hep B, his anti-HBs waned down or his HBsAg fell to undetected with his chronic infection. The last possibility will be antigen mutations inducing false-negative HBsAgresults. Studies found HBV DNA detected in anti-HBc positive patients, and lower prevalence in combined anti-HBc and anti-HBs positive patients than in isolated anti-HBc positive patients. The covalently closed circular DNA (cccDNA) in the nuclei of infected hepatocytes persist in chronic infection. When the HBV-infected hepatocytes are destroyed by the immune system, the cccDNA is released. This explains how HBV DNA can be detected or not in patients with isolated positive anti-HBc and how the levels could change in the same patient. In summary, HBsAg can be positive for a short period after vaccination and when infected from HBV, cccDNA stays persistent in the hepatocytes.