Her INR was 5.8 (normal range 1 to 2)/increasing INR; Scratched arm; Scratched arm and bled through 3 shirts, it kept bleeding; This is a spontaneous report from a contactable nurse (patient). A 64-year-old female patient received the first dose of BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE) (lot number EC1284), via an unspecified route of administration administered to left arm/deltoid on 29Dec2020 13:15 at single dose for COVID-19 immunization at a research medical facility; and received warfarin sodium (COUMADIN, strength 2 mg), oral (by mouth) from an unspecified date in 2017 and ongoing at "3 1/2 tablets once daily in the evening at 5:30pm (total 7mg)" for metal heart valve. The patient's medical history included had the surgery (for her metal heart valve), about 01Mar in 2017 (about 4 years ago) and so she thought she had been on Coumadin for about 4 years, had been on the 7mg dose for over a year; and has a history of metal heart valve and takes Coumadin for the metal heart valve. Denied illness. Denied family medical history relevant to event. There were no concomitant medications. The patient previously received Shingrix vaccine in past and remenbered she had the usual side effects from it, had mild symptoms. History of all previous immunization with the Pfizer vaccine considered as suspect was none. The patient did not receive any other vaccines the same date of the Pfizer Suspect or 4 weeks prior. On Jan2021, the patient experienced scratched arm and bled through 3 shirts, it kept bleeding. On 04Jan2021, her international normalised ratio (INR) was 5.8 (normal range 1 to 2). The events did not lead to emergency room visit, however led to physician office visit. The events were reported as serious medically significant. The nurse got the first Pfizer COVID-19 shot on 29Dec2020 because she is a healthcare provider. She wanted information on increasing INR. The nurse has a history of metal heart valve and takes Coumadin. Her INR was typically 1.7 to 2.3. She reported her last INR, before the covid-19 vaccine was given, was "some time ago" but it had not varied much over the years. Normally she got her INR run and it was about 2.  She had to be scheduled for her INR on the 04Jan2021 and it was 5.8 (normal range 1 to 2) and they asked about anything that may have changed and the only thing was that she got her first shot. The nurse reported not having any changes in her medications, food, or life style to account for the change, other than receiving the COVID-19 vaccine. The patient stated that it could be a serious problem if she had an accident or fell and started bleeding. A normal person's lab result is between 1 and 2, but they like to keep people with the metal heart valves between 2 and 3. She had been bleeding. She had barely scratched her arm the other day and went through 3 shirts because she kept bleeding. This is more than unusual for her, it's kind of unusual.  Getting the vaccine is the only variant she has had since getting her last INR. The patient underwent lab tests and procedures which included INR (normal range 1 to 2): typically 1.7 to 2.3 on an unspecified date; it's about 2 on an unspecified date: and 5.8 on 04Jan2021. The action taken in response to the events for warfarin sodium was dose not changed. The outcome of the event INR was 5.8 was not recovered, for the other events was unknown. The nurse (patient) assessed the event "INR was 5.8; it's normally about 2" as related to the COVID-19 vaccine.; Sender's Comments: Based on available information, a possible contributory role of the subject product, BNT162B2 vaccine, cannot be excluded for the reported events of International normalised ratio increased and wound hemorrhage due to temporal relationship.  There is limited information provided in this report.  Additional information is needed to better assess the case, including complete medical history, diagnostics coagulation panel, counteractive treatment measures and concomitant medications.  This case will be reassessed once additional information is 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 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.