COVID-19 vaccine-associated liver injury and autoimmune hepatitis: a case series

Background: Coronavirus disease 2019 (COVID-19) vaccines have significantly reduced global morbidity and mortality. While generally safe, rare immune-mediated liver injuries, including autoimmune hepatitis (AIH) and drug-induced liver injury have been reported post-vaccination. Case series: We present three cases that developed liver injury following Pfizer-BioNTech (BNT162b2) COVID-19 vaccination. Case 1 describes a 64-year-old female with new-onset AIH confirmed by serology, histology, and clinical response to corticosteroids. Case 2 is a 36-year-old female who developed transient liver injury that resolved without immunosuppressive therapy. Case 3 involves a 35-year-old male with a history of AIH in remission who experienced a flare, requiring intensification of immunosuppressive treatment. Discussion: The mechanisms underlying liver injuries following COVID-19 vaccination remain incompletely understood, and a causal relationship has not been definitively established. One possible mechanism is molecular mimicry, in which the immune system targets liver cells after recognizing similarities with viral spike proteins. Vaccine adjuvants may also contribute to immune dysregulation in individuals with certain genetic factors like HLA-DR3 and HLA-DR4, which have been linked to AIH. Multiple reviews of vaccine-associated liver injury suggest that the majority of patients improve with immunosuppressive therapy, although there have been rare reports of severe presentations, including progression to liver failure. Conclusion: Although rare, COVID-19 vaccines may be associated with various forms of liver injury. This case series highlights the heterogeneous clinical spectrum and disease course of COVID-19 vaccine-associated liver injuries, ranging from transient liver enzyme abnormalities to more persistent disease ,such as autoimmune hepatitis, requiring treatment. While causality can not be established, these findings emphasize the importance of clinical vigilance and individualized assessment in at-risk populations.