# Acute Severe Hepatitis B Virus Infection in Previously Vaccinated Patient during Acalabrutinib Treatment

## TL;DR

A fully vaccinated patient developed severe hepatitis B during acalabrutinib treatment, leading to liver failure and transplantation.

## Contribution

Reports a rare case of HBV reactivation in a vaccinated patient on acalabrutinib, highlighting the need for vigilance.

## Key findings

- A patient with adequate HBV antibodies developed acute HBV infection during acalabrutinib therapy.
- The infection progressed to liver failure requiring transplantation despite prior vaccination.
- HBV should be considered in the differential diagnosis of jaundice in patients on acalabrutinib.

## Abstract

We describe acute severe hepatitis B virus (HBV) infection with liver failure requiring transplantation in a patient in Poland treated with acalabrutinib. The patient was fully vaccinated against HBV and had adequate HBV antibody titers and no HBV exposure documented before therapy. Differential diagnoses for jaundice should consider HBV in patients receiving acalabrutunib.