prior to onset of event she did not have any rheumatoid arthritis problems in her knees; additional swelling in her knees; feels like she is gaining weight; can't get her brain to work; more swelling on her waist and back/Additional swelling around her waist/ looks like she has lumps; This is a spontaneous report from a contactable consumer (patient).   A 69-year-old female patient received bnt162b2 (BNT162B2), dose 2 via an unspecified route of administration (at the age of 69-years-old), administered in Arm Left on 08Apr2021 14:30 (Lot Number: EW0151; Expiration Date: 11Apr2021) as single dose for COVID-19 immunization. Medical history included rheumatoid arthritis from 2020 and ongoing (fought with it all last year in 2020; but was not diagnosed with rheumatoid arthritis until Feb2021), ongoing chronic obstructive pulmonary disease (probably really got with it about 2012), Breast cancer survivor from 2006 to 2006, and bone density. Concomitant medications included cyanocobalamin (B12 [CYANOCOBALAMIN]) taken for an unspecified indication from 16Mar2021 to an unspecified stop date; cortisone (CORTISONE) taken for an unspecified indication from 01Feb2021 to 01Feb2021; methotrexate (METHOTREXATE) taken for rheumatoid arthritis from 06Feb2021 to an unspecified stop date; denosumab (PROLIA) taken for bone density abnormal from 16Mar2021 to an unspecified stop date. The patient previously received bnt162b2 (BNT162B2), dose 1 via an unspecified route of administration (at the age of 69-years-old), administered in Arm Left on 12Mar2021 about 16:00-16:30 (Lot Number: EN6204) as single dose for COVID-19 immunization and experienced additional swelling in her knees and rheumatoid arthritis. The patient had preexisting condition of Rheumatoid arthritis prior to any Pfizer-BioNTech COVID-19 Vaccine. Prior to onset of this event, with her rheumatoid arthritis, she did not have any rheumatoid arthritis problems in her knees. With the rheumatoid arthritis it has always been in her hands and arms. She was taking Methotrexate for Rheumatoid arthritis. Rheumatologist told her that additional swelling in her knees event was rheumatoid arthritis. After second dose of Pfizer-BioNTech COVID-19 Vaccine she reported additional swelling around her waist. She had second dose of Pfizer-BioNTech COVID-19 Vaccine shot on 08Apr2021. On 11Apr2021 she noticed additional swelling around her waist. She asked if these swelling events are a side effect of the Pfizer-BioNTech COVID-19 Vaccine, or in combination with her rheumatoid arthritis. Onset time was about 05:30-06:00 after she took a shower, pretty much the same thing as with the first dose: additional swelling in her knees. She noticed swelling around the waist, going towards the back which didn't look right on 11Apr2021. There's no pain at all, it just looks like she has lumps. She has had no other effects from the Pfizer-BioNTech COVID-19 Vaccine other than feels like she is gaining weight. Patient reported no other relevant concomitant products or other medical conditions. She mentioned regarding Methotrexate that they tell her this is a high-quality drug that knocks the immune system down. While providing dates of concomitant product doses caller mentioned she can't get her brain to work on an unspecified date. The outcome of the events "prior to onset of event she did not have any rheumatoid arthritis problems in her knees" and "more swelling on her waist and back/Additional swelling around her waist/ looks like she has lumps" was not recovered while for the rest of the events was unknown. The event "prior to onset of event she did not have any rheumatoid arthritis problems in her knees" was considered as serious (medically significant).  No follow-up attempts are completed; information about batch/lot cannot be obtained.