feels a little different than normal; leg started bothering her/right leg bothered her; couldn't stand on my right leg, it wouldn't hold me; little more tired; my leg is hot, warm and a little swollen, and it aches.; my leg is hot, warm and a little swollen, and it aches.; my leg is hot, warm and a little swollen, and it aches.; This is a spontaneous report from a contactable consumer or other non hcp (Patient). An 87-year-old female patient received bnt162b2 (BNT162B2 formulation: Solution for injection, Batch/Lot Number: EN6204), dose 2 via an unspecified route of administration, administered in Arm Right (right shoulder) on 27Feb2021 as DOSE 2, SINGLE (at the age of 87-year-old) for covid-19 immunisation. Time the vaccination was given for both doses were given between 10:15 AM and 10:30 AM. Medical history included 2 total knee replacements (replacement on the right side the last one in July or June2003), Pacemaker (It was fine) and swelling joints from an unknown date and unknown if ongoing. It was reported that knee replacements was fine. It was just the right one with loose parts. She was not sure if she did something unintentionally to cause it to flare up, but it feels different. There were no concomitant medications. Historical vaccine included first dose of bnt162b2 on 06Feb2021 (Batch/lot number: EN5318, right arm (right shoulder) (at the age of 87-year-old) for covid-19 immunisation and 1st dose didn't bother patient at all. No additional vaccines administered on same date of the Pfizer suspect. No prior vaccinations within 4 weeks before COVID-19 Vaccines. No events reported following prior vaccinations. It was reported that the patient leg gave out in Jan2020 and the whole year of 2020 she was in her house. It was reported that after the second dose on 28Feb2021, the patient felt a little more tired than usual. On Monday (01Mar2021), the patient was out of sink, then on Tuesday (02Mar2021), the patient got up and couldn't stand on right leg, it wouldn't hold the patient. On 03Mar2021, the patient stated that right leg bothered her. Wednesday morning (on 03Mar2021), when she got up, she couldn't stand on it. She sat for a minute and then could stand The patient got cane and was able to go downstairs and get her coffee. She realized that her leg was bothering her and achy. She has an electric wheelchair, and she has used it all week because her leg was bothering her. She got the wheelchair when she saw her orthopedic doctor (Prior to getting the vaccine) about the swelling joints and she was told it had gotten loose and they can't do anything about it due to her age. She just got the electric wheelchair recently. The discomfort in the leg was different that it has been. It was stated that electric wheelchair which never used it before by patient. The patient stated leg was hot, warm, a little swollen and it aches and she felt little different than normal on an unknown date. The patient stated knee replacement had to done for other leg, but this one always gives her a little trouble. Now it's loose and they can't replace it because of her age, it's been bothering her all last week, and it feels different than last time it bothers her. The patient son suggested to her, to checked it as it could be a clot. It was reported that the patient doesn't remember things as she was too old to put that in and her brain was too full with other things. AE's does not require visit to Emergency room and physician office. The outcome of event little more tired was recovered on 01Mar2021 and leg started bothering her was not recovered and outcome of other events reported as unknown.  No follow-up attempts are possible. No further information is expected.