Abstract: PUB090
When Prevention Mimics Infection: A Case of Vaccine-Induced Hepatitis B Surface Antigen Positivity
Session Information
Category: Dialysis
- 801 Dialysis: Hemodialysis and Frequent Dialysis
Authors
- Ali, Omar, Albany Medical Center, Albany, New York, United States
- Gosmanova, Elvira O., Albany Medical Center, Albany, New York, United States
Introduction
False-positive hepatitis B surface antigen (HBsAg) test results are uncommon (<1%) with modern assays but can complicate dialysis care due to isolation protocols. Known causes of false-positive HBsAg include malignancy, autoimmune diseases, and infections like Epstein-Barr virus or HIV. We present a case of isolated HBsAg positivity after recent vaccination in a patient on hemodialysis who had no evidence of hepatitis B virus (HBV) infection.
Case Description
A 68-year-old male with ESRD on hemodialysis received several vaccinations, including a second dose of Hep B a week prior (Recombinant HBsAg + CpG adjuvant), and[EG1] RSV (Bivalent recombinant protein subunit) and Tdap (Toxoid) three weeks before routine HBsAg screening. Earlier hepatitis B serologies were negative. The screening revealed isolated HBsAg positivity and negative anti-HBc (total and IgM) antibodies and HBV DNA. A confirmatory HBsAg neutralization assay was negative. Repeat testing after four weeks confirmed a negative HBsAg result. The patient remained asymptomatic and was briefly isolated per protocol until confirmatory testing was completed.
Discussion
Transient HBsAg antigenemia following hepatitis B vaccination is well-documented and usually persists on confirmatory assays. These assays utilize human anti-HBs antibodies to neutralize the true antigen, and a signal reduction of more than 50% confirms the presence of true HBsAg. In the current case, a negative confirmatory result suggests that the hepatitis B vaccine alone did not cause the initial HBsAg reactivity.
The patient also received RSV and Tdap vaccines three weeks prior. While false-positive HBsAg results have been reported after COVID-19 and influenza vaccinations, associations with RSV or Tdap vaccines have not been documented. It is plausible that RSV and/or Tdap vaccination caused the transient generation of heterophil antibodies, which interfered with the HBsAg immunoassay and yielded false results.
This case highlights the importance of interpreting isolated HBsAg reactivity cautiously, especially in hemodialysis, where unnecessary isolation can complicate care delivery. Vigilance is required when assessing HBsAg results in recently vaccinated individuals.