AUTOIMMUNE HEPATITIS; This spontaneous report was received from other health professional via literature. This report concerned a 45 year old female of an unspecified race and ethnicity. The objective of the authors was to present a unique case of AIH (autoimmune hepatitis) in the setting of the Janssen Covid-19 vaccine. The patient's height, and weight were not reported. The patient's concurrent conditions included: HTN (Hypertension), DM (Diabetes mellitus), GERD (Gastrooesophageal reflux disease), and obesity. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin, batch number and expiry date were not reported) dose, start therapy date were not reported, 1 total administered for covid-19 prophylaxis. The batch number was not reported. Per procedure, no follow-up will be requested for this case. Concomitant medications included hydrochlorothiazide and occasionally seamoss supplements. On an unspecified date, patient presented from her primary care physician's office with abnormal liver chemistries in a hepatocellular pattern. The patient received a single dose of the Janssen SARS CoV-2 vaccination (Johnson and Johnson). Her hepatic profile showed AST (Aspartate aminotransferase) 1119, ALT (Alanine aminotransferase) 988, AP 9 Alkaline phosphatase) 130, and total bilirubin of 1.5 (R-factor 22.8). Given the magnitude and rapidity of the elevated chemistries a broad serologic workup was initiated. She was negative for hepatitis A, B, and C, as well as HSV (Herpes simplex virus) 1/2, EBV (Epstein-Barr virus), CMV (Cytomegalovirus), HIV (human immunodeficiency viruses), VZV (Varicella virus), and adenovirus. Her ferritin and iron studies did not suggest iron overload. Her ceruloplasmin and alpha 1 antitrypsin levels were within acceptable ranges. Her ANA (Antinuclear antibody) was negative; her smooth muscle antibody was positive (1:320), IgG (immunoglobulin G) was elevated to 3,451 mg/dL. Her urine toxin screen was negative. She had chronically been on HCTZ (hydrochlorothiazide) and took occasionally seamoss supplements. She denied using tylenol or any other over the counter or herbal supplements. Her liver chemistries prior to vaccination were AST 17, ALT 14, AP 52, and total bilirubin of 0.3. She subsequently underwent a liver biopsy which showed moderate (grade 3) lobular inflammatory activity, mild (grade 2) periportal activity, and mild (stage 2) fibrosis with an abundance of plasma cells consistent with autoimmune hepatitis. Treatment was initiated with oral prednisone with a resulting improvement in her liver chemistries. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient was recovering from autoimmune hepatitis. The authors concluded that autoimmune hepatitis in the setting of recent administration COVID 19 vaccine administration has been rarely reported. They presented a unique case of COVID vaccine induced autoimmune hepatitis from a non-mRNA based vaccine. It has been suggested that possible mechanisms may include molecular mimicry or bystander activation of dormant autoreactive T-helper cells for both tissue-specific and non-tissue-specific reactions. Their aim was to shed light to this interesting paradigm and to spark the scientific discourse to further delineate potential mechanisms leading to this uncommon complication. This report was serious (Other Medically Important Condition).; Sender's Comments: V0-20230557328- Autoimmune hepatitis- The event has a unknown/unclear temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event. Therefore, the WHO Causality is considered indeterminate. The company causality is considered unassessable.