Gastroparesis; This is a literature report.  A 57 year-old male patient received bnt162b2 (Pfizer-BioNTech COVID-19 vaccine), administration date Dec2020 (Batch/Lot number: unknown) as dose 1, single and (Batch/Lot number: unknown) as dose  2, single for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. The following information was reported: IMPAIRED GASTRIC EMPTYING (medically significant), outcome "recovered", described as "Gastroparesis". The event "gastroparesis" was evaluated at the emergency room visit. The patient underwent the following laboratory tests and procedures: computerised tomogram: unremarkable findings. Therapeutic measures were taken as a result of impaired gastric emptying.  We present here a case of acute onset of gastroparesis after the Pfizer-BioNTech COVID-19 vaccine. A previously healthy 57-year-old man received dose one of the Pfizer-BioNTech COVID-19 vaccine in December 2020. Five days after vaccination, he developed the onset of intractable nausea, vomiting, and hiccups. Over the following week, he required 3 emergency department visits for intravenous fluid resuscitation and symptoms refractory to oral prescription antiemetics including ondansetron and prochlorperazine. He was subsequently trialed on baclofen without symptom relief. Metoclopramide, for presumed gastroparesis, provided significant relief, but it was discontinued after a few days because of extra pyramidal symptoms of akathisia. One week after receiving the vaccine, computed tomography of the abdomen and pelvis was obtained with unremarkable findings. Because of persistent symptoms, he was started on erythromycin with some improvement in symptoms. His symptoms nearly resolved on the second week, and he was able to taper off prokinetics. Twenty-three days after receiving dose one, the patient received his second dose of the Pfizer-BioNTech COVID-19 vaccine. Within hours of receiving dose 2, he developed recurrent, intractable nausea, vomiting, and hiccups. Symptoms were associated with sitophobia and near syncope. He was started on dose-escalating domperidone with minimal improvement. A nuclear medicine gastric emptying study showed 15% of gastric contents remaining at 4 hours, consistent with delayed gastric emptying. Suspecting an immune-mediated phenome non, a trial of high-dose famotidine provided no relief, but within days of starting a course of prednisone, his symptoms resolved. He was able to successfully taper off prednisone with a 2-week taper. He remains asymptomatic 2 months after cessation of steroids. To our knowledge, this is the first reported case of gastroparesis after the Pfizer-BioNTech COVID-19 vaccination. As demonstrated in our case, symptoms can be severe and refractory to several first-line agents used to treat this condition. There is a recently reported case of SARS-CoV-2 infection presenting as a gastroparesis flare in a patient with known diabetic gastroparesis. Similar cases have been reported with other viral infections, but postvaccination gastro paresis is a rarely reported entity. Our patient responded to steroids, we therefore hypothesize that the mechanism of action of messenger RNA vaccines may precipitate immune-mediated gastroparesis. Providers should be aware of this possible gastrointestinal side effect of the COVID 19 vaccine if patients present with con sistent symptoms after vaccination, and consideration should be given to early use of limited courses of immunosuppression. After a standard meal using 0.5 mCi of sulfur colloid, statis images were obtained from anterior projection (left top) and posterior projection (left bottom) immediately, and then at 60, 120, and 240 minutes. From the measurement of counts on the anterior and posterior projections, gastric retention of the radiotracer was calculated using the geo metric mean. The gastric retention is borderline at 120 minutes but is above normal limits on the 240 minutes, which is consistent with slow gastric emptying.; Sender's Comments: Based on the information provided and plausible temporal association, the causality between BNT162B2 and event impaired gastric emptying  (gastroparesis)  cannot be completely excluded.  The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to regulatory authorities, Ethics Committees, and Investigators, as appropriate.,Linked Report(s) : US-PFIZER INC-202101755909 Same article/ drug/patient and different event