onset severe pain in her left foot and until now she is still unable to walk/ Very abrupt onset of severe pain in left foot; Unable to walk; when went in hospital caller was 195 pounds and is probably considerably less than that now; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team. The reporter is the patient.  A 76-year-old female patient received BNT162b2 (BNT162B2), on 30Oct2021 as dose 3 (booster), single (Lot number: FD0809) at the age of 76 years, in arm for covid-19 immunisation. The patient's relevant medical history included: "Heart disease", start date: 16Feb2016 (ongoing), notes: heart disease Major health condition is heart disease. Had three stents placed on 16Feb2016.; "Cancer", start date: 2013 (unspecified if ongoing), notes: Cancer Clear of cancer, diagnosed with 9 years ago. There were no concomitant medications. Vaccination history included: BNT162b2 (Second dose: 09Feb2021, lot: EL3247, NDC: Unknown , expiration: unknown, Route of administration: arm, doesn't remember if left or right arm, Caller had no reaction where administered, second dose.), administration date: 09Feb2021, when the patient was 75-year-old, for Covid-19 immunization; BNT162b2 (First dose: 19Jan2021 , lot: EL0142, NDC: Unknown , expiration: Unknown , Route of administration: arm, doesn't remember if left or right arm), administration date: 19Jan2021, when the patient was 75-year-old, for Covid-19 immunization. The following information was reported: GAIT INABILITY (caused and prolonged hospitalization) with onset 17Apr2022, outcome "not recovered", described as "Unable to walk"; PAIN IN EXTREMITY (caused and prolonged hospitalization) with onset 17Apr2022, outcome "not recovered", described as "onset severe pain in her left foot and until now she is still unable to walk/ Very abrupt onset of severe pain in left foot"; WEIGHT DECREASED (non-serious) with onset 17Apr2022, outcome "unknown", described as "when went in hospital caller was 195 pounds and is probably considerably less than that now". The patient was hospitalized and prolonged hospitalization for pain in extremity, gait inability (start date: 17Apr2022, discharge date: 28Apr2022, hospitalization duration: 11 day(s)). The events "onset severe pain in her left foot and until now she is still unable to walk/ very abrupt onset of severe pain in left foot" and "unable to walk" required emergency room visit. The patient underwent the following laboratory tests and procedures: Weight: (17Apr2022) Less, notes: when went in hospital caller was 195 pounds and is probably considerably less than that now. Therapeutic measures were taken as a result of pain in extremity, gait inability.  Clinical course: Patient had the Pfizer COVID-19 Vaccine first, second and booster dose. Patient experienced an onset severe pain in her left foot and until now she is still unable to walk. Patient stated that she was hospitalized for 12 days with morphine, and after that her foot continues to be swollen and she can't walk. Patient wanted to know if this adverse reaction was reported before? Patient stated that there is no definitive diagnosis as to what could have caused that, and patient wanted to make this report to help people in case someone else had this adverse reaction. Time the vaccination was given: First dose: unknown, second dose: scheduled through hospital on 09Feb2021 at 13:00, but was not given at that exact time, reported and stood in line at 1300 to receive second dose, booster dose: unknown. Anatomical Location of Administration of Pfizer vaccine considered as suspect: arm, doesn't remember if left or right arm.  Follow-up attempts are completed. No further information is expected.