They were taking fluid from the patient's knee, it had a lot of blood in the fluid; taking fluid from the patient's knee; arthritis pain; knee was bone on bone; knee with bone on bone and it was swelling and irritated; knee with bone on bone and it was swelling and irritated; changed the way he walked his gait; Legs are not aligned because of that hip/ right side of his knee join was up; All of his lower body hurt; joint pain was more wide spreading/ ankles and sole feet hurt; Mild headaches; ankles and sole feet hurt; This is a solicited report received by Pfizer from Regulatory Authority operations. A contactable physician reported that a 71-years-old male patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE), dose 1 via an unspecified route of administration on an unspecified date (Batch/Lot number was not reported) as single dose for covid-19 immunisation; initiated the use of oral Jakafi (ruxolitinib) 20 mg tablets twice a day from on unknown date and ongoing for myelofibrosis. Co-suspect medication included cortisone injection administered on unspecified date in Jul2020, ibuprofen from unknown date as needed for an unknown indication. Medical history included osteoarthritic hip/Left his is osteoarthritic from 2010, myelofibrosis, ongoing osteoporosis in left hip joint and hip discomfort. Concomitant medications included: Vitamin B12 (cyanocobalamin), Zantac (ranitidine hydrochloride), Prenatal Multivitamins (minerals NOS, vitamins NOS), Low-dose Aspirin (acetylsalicylic acid), diltiazem, Tums (calcium carbonate), Aleve (naproxen sodium), and famotidine. On an unspecific date, in the last 6 weeks, the patient was not taking ibuprofen; the patient was taking paracetamol for pain when he had arthritis pain, the patient had a knee with bone on bone and it was swelling and irritated. The doctor recommended to not take ibuprofen because when they were taking fluid from the patient's knee, it had a lot of blood in it the fluid. The patient had to go in twice in the last 4 weeks from the time of report to take fluid out of his knee. The patient had to spend a lot of time with ice in his Knees and elevated it 2-3 times a day just to be able to get around. The patient had osteoporosis in his left hip joint and that was why he had a lot of hip discomfort, the patient had that for three or four years and did physical therapy to try to keep his hip mobile. The doctor suggested that the hip pain changed the way he walked and that cause the knee pain. His legs were not aligned because if his hip. The right side of his knee join was up. The patient had his first covid vaccine shot and for 2 weeks, all of his lower body hurt. His joint pain was more wide spreading, his hands and upper arms did not hurt like that. The patient had mild headaches for a couple of days. His knees and leg joints were fine but his ankles and sole feet hurt but the pain was diminished. The action taken in response to the events, for cortisone was unknown, for ibuprofen was temporarily withdrawn, for ruxolitinib phosphate was dose not changed. The outcome of the events joint pain, knee is bone on bone was not recovered/not resolved. The outcome of the remaining events was unknown.  The reporter's assessment of the causal relationship of the events with the suspect product was not provided at the time of this report. Since no determination has been received, the case is managed based on the company causality assessment.  No follow-up attempts are possible, information about batch number cannot be obtained.; Sender's Comments: Based on a compatible temporal association and known product safety profile, there was a reasonable possibility that the reported events of arthralgia and headache were related to BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE). All other reported events are attributed to intercurrent medical conditions and assessed unrelated to BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE)