Letter to the editor: Autoimmune hepatitis after COVID‐19 vaccination: Need for population‐based epidemiological study

Abstract

We have read with interest the study published by Palla et al.[1] regarding a possible link between COVID-19 vaccination and the development of autoimmune hepatitis (AIH).[2, 3] We propose the need for population-based studies to gather data on the incidence, severity, and clinical features of COVID-19 vaccination-induced AIH by describing three cases of COVID-19 vaccination-induced AIH from our institution between January and October 2021. Case 1 involves an 80-year-old woman diagnosed with a liver injury (aspartate aminotransferase 995 U/L, alanine aminotransferase 974 U/L, total bilirubin 3.5 mg/dl), based on her laboratory results 10 days after receiving the second dose of the BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine. The antinuclear antibody test was positive at a titer of 1:40. The serum immunoglobulin G level was 1936 mg/dl. A full serological screen excluded other causes of acute liver disease. Liver biopsy revealed lymphoplasmacytic infiltration in the portal area with moderate interface hepatitis, compatible with AIH (Figure 1A,B). She was treated with prednisone at an initial dose of 0.8 mg/kg/day. The dose was subsequently tapered to 10 mg/week on noting progressive improvement in her laboratory results (Figure 1C). Two other patients exhibited similar findings. One was a 75-year-old woman who developed AIH 4 days after the second dose of BNT162b2, whereas the other was a 78-year-old woman who developed AIH 7 days after her first dose of BNT162b2. The histological features of the liver biopsy specimen and the clinical course of the two patients are presented in Figures S1 and S2. The clinical characteristics of the patients are presented in Table S1. All 3 patients underwent regular blood testing because of underlying diseases without anterior liver injury. Epidemiological studies on post-COVID-19 vaccination myocarditis have shown that most cases occurred within 1 month of vaccination.[4] This was consistent with the three reported cases. Approximately 0.9 million people had received two vaccine doses in our medical region by October 31, 2021. Therefore, the incidence of AIH due to COVID-19 vaccination was estimated to be three cases per million people. When managing new or exacerbated AIH cases, the patient’s COVID-19 vaccination history should be investigated. Rigorous population-based studies are required in the future to evaluate the incidence of COVID-19 vaccine–induced AIH. We thank Masao Nishiya for a valuable discussion on the interpretation of the liver biopsy specimens. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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