Exacerbation of Hepatic Porphyria; This is a spontaneous report from a contactable pharmacist (patient). A 50-year-old male patient (Weight: 127.01 kg, Height: 178 cm) received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE) via an unspecified route of administration, administered in Arm Left, DOSE 1 SINGLE on 04Apr2021 Afternoon (Lot Number: EP7533) and DOSE 2 SINGLE on 25Apr2021 (Lot Number: EW0167) for covid-19 immunisation. Vaccination Facility Type: Pharmacy Clinic. Medical history included Hepatic Porphyria from Apr2012 and ongoing (Caller states he knew he had it 10 years ago, but he was diagnosed in April. Caller states so 2012, but it took that long to have another attack that was serious enough to run the test) and ongoing Ulcerative colitis started 25 years ago. There were no concomitant medications. None Additional Vaccines Administered on Same Date of the Pfizer Suspect. Prior Vaccinations (within 4 weeks) or AE(s) following prior vaccinations: None. Caller states he is reluctant to report an drug reaction unless he is 100% sure, well unless he is more than 50% sure, but he is confused, and they have ruled everything else out and he needs help. Caller states he has been hospitalized the past 27/55 days in the hospital due to the severity. Caller states he has Hepatic Porphyria. Caller states since receiving the Covid Vaccine, he has been having an exacerbation. Caller states it is an extremely rare genetic condition, where he can not make heme, he is missing an enzyme to make it and get past the 6th step. Caller states all the heme is produced only by one chromosome. Caller states he is guessing that the Pfizer vaccine, being MRNA, is it self amplifying? Caller states he has Hepatic Porphyria, but he has been able to manage it successfully since he discovered he had it the past decade or so, but since he took the vaccine, he has been getting a non stop attack, an exacerbation. Causation: caller states they have ruled everything else out, and the way it works would make since. Hospitalization #1: 18Apr2021-23Apr2021. States he got out that Sunday and had the second dose pm 25Apr2021 and then he was hospitalized again the following week. Hospitalization #2: 05May2021-08May2021. States he got out that week and was hospitalized again. Hospitalization #3: 26May2021-09Jun2021 for a 2 week sent. Hospitalization #4: 11Jun2021-12Jun2021 for 2 Days. Caller states he is dealing with an acute attack right now, and he has not been under control. Caller states he hopes it was the vaccine causing it and it runs itself out. Caller asks, how long does it take for the action to run out? Caller stats he usually only gets an attack for one day, once a year or every other year. Symptoms of these attacks include "intense abdominal pain and neuro symptoms" and these symptoms have been "unrelenting, non-stop" since being vaccinated. He would like to know how long after vaccination the Pfizer-Biontech Covid19 vaccine remains in the body? Also, is there an increased demand for the production of heme anywhere in the pharmacological process for an mRNA vaccine? He stated that if there is an increased demand for heme, this would explain his symptoms. He wants to know how long he should expect the process to last or resolve? The reporter considered the event as serious due to Caused/prolonged hospitalization and Disabling/Incapacitating. Treatment: Pan hematin. The event Exacerbation of Hepatic Porphyria required a visit to Emergency Room and Physician Office, states he is also seeing a hematologist. The outcome of the event was not recovered. The pharmacist considered the event Exacerbation of Hepatic Porphyria is Related to Covid Vaccine.; Sender's Comments: A possible contributory role of the suspect drug to the reported event "Exacerbation of Hepatic Porphyria" cannot be completely excluded based on temporal association. This case will be re-assessed when additional information becomes available.   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 identifies as part of this review, as well as any appropriate action in response, will be promptly notifies to Regulatory Authorities, Ethics Committees and Investigators, as appropriate.