Acute Hepatitis B Infection in a Patient With Confirmed Immunity on Long-Acting Cabotegravir/Rilpivirine.

Long-acting injectable formulation of cabotegravir/rilpivirine (CAB/RPV) is a promising novel maintenance therapy for HIV infection. However, coinfection with active hepatitis B virus (HBV) infection is a contraindication to initiating this therapy. Despite guidelines, patients with HBV immunity can still contract acute HBV infection. We report a case of a 30-year-old man with HIV who transitioned from antiretroviral therapy to CAB/RPV and had confirmed HBV immunity. The patient, though asymptomatic, showed significantly elevated liver function tests (LFTs) before his monthly CAB/RPV injection. He was hospitalized and diagnosed with acute HBV infection. His LFTs improved, and he was taken off CAB/RPV and returned to antiretroviral therapy for the treatment of HIV and HBV. During subsequent follow-ups as an outpatient, the patient's LFTs normalized, and his HBV viral load significantly decreased. This case highlights the potential need for routine HBV testing in patients on CAB/RPV therapy.