Acute hepatitis following mRNA BNT162b2 COVID-19 vaccination

BACKGROUND: Widespread administration of COVID-19 vaccinations have led to reports of rare but potentially serious side effects. METHODS: We present two cases of acute hepatitis following mRNA BNT162b2 (Comirnaty, Pfizer-BioNTech) vaccination. RESULTS: A 25-year-old male presented to hospital with progressive jaundice 5 days following his second dose of Comirnaty. Initial bloodwork revealed severe hepatocellular enzyme elevation and conjugated hyperbilirubinemia with preserved INR. Extensive serologic workup was negative, with normal imaging. Percutaneous liver biopsy was performed and revealed acute cholestatic hepatitis possibly related to drug-induced liver injury. He was started on prednisone 40 mg daily with good initial response but had a second flare; a biopsy was repeated which showed near-identical findings. Steroids were discontinued given non-response and the patient had gradual near complete resolution of liver enzymes and hyperbilirubinemia. A 32-year-old male presented with a 4-week history of nausea followed by progressive choluria, jaundice, and pruritis. He received his second dose of Comirnaty vaccination two weeks prior to presentation. Initial bloodwork showed mixed enzyme elevation with hyperbilirubinemia. Serological workup and imaging were unrevealing. He underwent liver biopsy which showed severe intrahepatic cholestasis, with drug-induced liver injury being suggested as most likely cause. His course was self-limited with resolution of serological abnormalities and symptoms. CONCLUSIONS: While overwhelmingly safe on a population level, our case series illustrate two cases of acute icteric hepatitis following mRNA BNT162b2 vaccination. Clinicians should be aware of this association with hepatic inflammation and consider vaccine history an important component of evaluating patients with acute liver injury.