The patient experienced occurrence of E.coli sepsis on 15Mar2021 and ended up in hospital; The patient experienced occurrence of E.coli sepsis on 15Mar2021 and ended up in hospital; The patient got so weak; This is a spontaneous report received from a contactable retired registered nurse (patient). An 85-year-old female patient received bnt162b2 (PFIZER-BIONTECH COVID-19 VACCINE), first dose via an unspecified route of administration, administered in arm left (left shoulder, but not certain) on 20Feb2021 11:30 (Batch/Lot Number: EN6701) at age of 85-year-old at single dose for COVID-19 immunization (the patient didn't want to catch COVID and wanted to have antibodies to fight it). Vaccine was not administered at known Facility. Medical history included first hospitalization for E.coli (Escherichia coli) sepsis was in Feb2021, prior to receiving the first dose Pfizer COVID Vaccine, the patient received more antibiotics from home health and the patient was in the hospital for five days from 01Feb2021 to 05Feb2021 and had the last antibiotic on 09Feb2021. Concomitant medications included ceftriaxone (ROCEPHIN) and cefalexin (KEFLEX) taken for E.coli sepsis from 15Mar2021 to 02Apr2021. Prior Vaccinations (within 4 weeks) there was not any other vaccinations within four weeks prior to the first administration date of the suspect vaccine. The patient experienced occurrence of E.coli sepsis on 15Mar2021 and ended up in hospital. The patient had been in the hospital again after receiving the first dose Pfizer COVID Vaccine for the patient's second occurrence of E. Coli sepsis.  The patient was in rehab by 01Apr2021 and was taken by medical transport at the hospital to receive her second dose Pfizer COVID Vaccine. The patient clarified she had E.coli sepsis twice. The patient's first hospitalization for E.coli sepsis was from 01Feb2021 to 05Feb2021, prior to receiving the first dose Pfizer COVID Vaccine. The caller's second hospitalization was from 15Mar2021 to 02Apr2021, the patient was in rehab for three weeks. The patient stated she was no longer on any antibiotics. The patient was on ceftriaxone first and then cefalexin, IV. The caller was in the emergency room on 15Mar2021 and they admitted the patient at health facility for three days, then they transported the patient to a bed in the rehab area because the patient needed another 21 doses of antibiotics and the patient needed to learn to walk again. The patient got so weak.  The patient was discharged on 02Apr2021. The event E.coli sepsis required visit to emergency room and physician office. Relevant tests were none. The outcome of the events was unknown.; Sender's Comments: Based on the limited information in the case, a possible contributory role of the suspect BNT162B2 cannot be excluded for the reported E.Coli Sepsis. 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.