Myositis/Inclusive Myositis, IBM; She cant walk up stairs anymore /She has to use a cane if on the floor or has to have someone help her get up /can't leave the house; Her legs were very heavy/Heavy leg syndrome; She couldn't walk up the stairs; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from medical information team.  A 59-year-old female patient received BNT162b2 (BNT162B2), on 09Jan2022 as dose 3 (booster), single (Lot number: 331308A, Expiration Date: Mar2022) at the age of 58 years, in left arm for covid-19 immunisation. The patient's relevant medical history included: "Rheumatoid arthritis" (ongoing), notes: Rheumatoid arthritis Diagnosed 5-year-ago. There were no concomitant medications. Vaccination history included: BNT162b2 (Dose: 01, Anatomical Location: left arm), administration date: 17Apr2021, when the patient was 57-year-old, for COVID-19 Immunization, reaction(s): "Her legs felt funny", "She didn't feel good after first vaccine"; BNT162b2 (Dose: 02, Anatomical Location: left arm), administration date: 04May2021, when the patient was 57-year-old, for COVID-19 Immunization, reaction(s): "Her legs felt more heavy/ Heavy Leg Syndrome", "Her legs got worse a day or too after second shot", "After the second vaccine she was sick for a week", "First dose of COVID-19 vaccine was given on 17Apr2021. The second dose of COVID-19 Vaccine was given on 04May2021". The following information was reported: LIMB DISCOMFORT (non-serious) with onset 2022, outcome "not recovered", described as "Her legs were very heavy/Heavy leg syndrome"; INCLUSION BODY MYOSITIS (medically significant) with onset 2022, outcome "not recovered", described as "Myositis/Inclusive Myositis, IBM"; LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (non-serious) with onset 2022, outcome "not recovered", described as "She cant walk up stairs anymore /She has to use a cane if on the floor or has to have someone help her get up /can't leave the house"; GAIT DISTURBANCE (non-serious) with onset 2022, outcome "not recovered", described as "She couldn't walk up the stairs". The event "her legs were very heavy/heavy leg syndrome" required physician office visit. The patient underwent the following laboratory tests and procedures: Muscle enzyme: 7500, notes: Muscle enzymes normally are 200, hers shot up to 7500 and then they got it down to 4500; 4500, notes: Muscle enzymes normally are 200, hers shot up to 7500 and then they got it down to 4500; 200, notes: Caller states the lab they drew was supposed to be 200 and is 7500. Therapeutic measures were taken as a result of inclusion body myositis, loss of personal independence in daily activities, limb discomfort, gait disturbance.   Clinical course: Caller was a care giver for his wife calling to report an A/E that she had with Pfizer COVID-19 vaccine. Caller states with first shot her legs felt funny but they didn't contribute it to the vaccine. 2nd shot her legs felt more heavy. Then with booster her legs were very heavy where she could not walk up the stairs and doctors diagnosed her with Heavy leg syndrome and then Myositis. Caller states that lab they drew was supposed to be 200 and is 7500. She was seeing a Rheumatologist that said never get another COVID vaccine and to report this. caller clarified that it was the day after the first shot that her legs felt funny. Legs were really heavy: it was six months later. Her legs got worse a day or too after second shot and that is when she went to general practitioner. She was having trouble lifting left leg. The general practitioner said she had Heavy Leg Syndrome. She did not feel good after first vaccine. After the second vaccine she was sick for a week. Then when she got booster she was laid out for a week again. She has never recovered after the booster. She cant walk up stairs anymore. She has to use a cane if on the floor or has to have someone help her get up. The rheumatologist does video conferences with doctors around the country. The rheumatologist said that half of the doctors are saying that they believe it is from the vaccine and the other half are on the fence. The next step is to go for a biopsy because none of the medicines are working. No further details provided. The rheumatologist does not think it is curable. They do not have health insurance. The rheumatologist has been her doctor since when she did have insurance. Then she lost her insurance and the rheumatologist did not turn his back on her and is still seeing her. Starting to lean towards Inclusive Myositis, IBM. She was so active before the vaccines with walking and swimming. Now she can not leave the house. She used to enjoy the garden and can not go outside now.  Follow-up attempts are completed. No further information is expected.