has 2 artificial knees an they have started swelling and one has become painful, one more than the other; has 2 artificial knees an they have started swelling and one has become painful, one more than the other; rash; could see the medicine dark under her skin where its spreading out; being in pain; knee has been numb; 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 71-year-old female patient received bnt162b2 (BNT162B2), administration date 24Sep2021 (Lot number: FF8839) at the age of 71 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "Blood pressure" (unspecified if ongoing), notes: controlled with medicine; "Eye surgery" (unspecified if ongoing), notes: Eye surgery; "artificial knees" (unspecified if ongoing). The patient's concomitant medications were not reported. Past drug history included: Naproxen, reaction(s): "stage 3 kidney disease", notes: The caller also has stage 3 kidney disease caused from Naproxen. The caller's heart is really strong, but she has calcium on the outside of the veins and was given nitro and is on medicine for that.; Nitro, notes: The caller also has stage 3 kidney disease caused from Naproxen. The caller's heart is really strong, but she has calcium on the outside of the veins and was given nitro and is on medicine for that. Vaccination history included: Bnt162b2 (First Dose: Received 09Feb2021, lot 9262, NDC unknown, and expiration date May2021.), administration date: 09Feb2021, when the patient was 70 years old, for COVID-19 Immunization, reaction(s): "rash on her shoulder"; Bnt162b2 (Second Dose: Received 09Mar2021, lot EN6201, NDC unknown, and expiration date Jun2020.), administration date: 09Mar2021, when the patient was 70 years old, for COVID-19 Immunization, reaction(s): "rash on her shoulder". The following information was reported: JOINT SWELLING (non-serious), ARTHRALGIA (non-serious), outcome "not recovered" and all described as "has 2 artificial knees and they have started swelling and one has become painful, one more than the other"; RASH (non-serious), outcome "unknown", described as "rash"; SKIN DISCOLOURATION (non-serious), outcome "unknown", described as "could see the medicine dark under her skin where its spreading out"; PAIN (non-serious), outcome "unknown", described as "being in pain"; HYPOAESTHESIA (non-serious), outcome "unknown", described as "knee has been numb". Relevant laboratory tests and procedures are available in the appropriate section.Additional information: Clinical course: It was reported that received three doses of the Pfizer-BioNTech COVID-19 vaccine for 12 years and older formulation. Prior to her vaccination, had two artificial knees. After her three doses began experiencing swelling on one on her knees and it has moved to the second knee as well. Patient wants to know is there any correlation with this swelling she is experiencing and her vaccination. She has had 2 of the regular ones and the booster and was due for another booster. The patient has 2 artificial knees and they have started swelling and one has become painful, one more than the other. The patient went to the orthopedic doctor and did a full body scan, and they also did a bore needle and took the fluid out. There was no infection, and nothing looks loose. The doctor doesn't know what was going on and was going to have to go in a look at it. Now the other leg is starting to swell the same way that the other one has. She has had no trouble after any of the vaccines other than a rash on the top of her shoulder for about a week and then some darkness that was fingering out where the medicine was. She has been one of the first ones to try to get her shots. The caller doesn't want to have this with the next booster dose. She also had a flu shot in the middle of all 3 of her Pfizer covid vaccine doses, it was the high flu shot dose because she is old. This is the fifth call that the patient has made. The patient is due for the fourth dose, but this didn't start until after the shots. The swelling was after the shots, and it keeps building up. She used to be in pain since she has had so many surgeries. It started to swell when the uses it and it really gets big and can be painful. The other leg has started in because she was favoring the other one. She doesn't understand what was happening because neither one showed anything was wrong. The patient cannot do a whole lot because of this, her husband has to help her up the stairs. The patient knee has been numb. Now the other leg was swelling and doing the same thing.No follow-up attempts are possible. No further information is expected.