tested positive; tested positive; severe pain in my legs, knees, and hip joints after walking for about 200 meters; can no longer carry loads up a flight of stairs; severe pain in my legs, knees, and hip joints after walking for about 200 meters; This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from product quality group. The reporter is the patient. Other Case identifier(s): MOD-2022-654886 (Moderna).  A patient (no qualifiers provided) received BNT162b2 (COMIRNATY), on 20Mar2021 as dose 1, single (Lot number: ER7812) for covid-19 immunisation. The patient's relevant medical history was not reported. Concomitant medication(s) included: VALSARTAN oral, start date: 2016 (ongoing). The following information was reported: DRUG INEFFECTIVE (medically significant), COVID-19 (medically significant) all with onset 06Apr2021, outcome "unknown" and all described as "tested positive"; LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (non-serious) with onset 2021, outcome "unknown", described as "can no longer carry loads up a flight of stairs"; ARTHRALGIA (non-serious) with onset 2021, 8 months 23 days after the suspect product(s) administration, outcome "unknown", PAIN IN EXTREMITY (non-serious) with onset 2021, outcome "unknown" and all described as "severe pain in my legs, knees, and hip joints after walking for about 200 meters". The patient underwent the following laboratory tests and procedures: SARS-CoV-2 test: (06Apr2021) Positive, notes: After 14days I tested positive If yes specify date: 06Apr2021,Test type: PCR; (May2021) Positive, notes: 4XPCR test was positive till the beginning of May. Therapeutic measures were taken as a result of arthralgia, loss of personal independence in daily activities, pain in extremity.  Clinical course: At the moment patient can no longer carry loads up flight of stairs and have severe pain in their leg, Knees and hip joints after walking for about 200 meters. Everything is okay from the wrist up. Information on the Moderna vaccine for Covid-19 included Dose 2 on 11Dec2021 at 11:00 of Batch no: LOT216044. Dose 3, Dose 4 was not received. Allergies to medicines, foods or other products were None. Acute illness on the vaccination date and until the previous month were None. Date of occurrence was 13Dec2021 and in progress. Chronic or long term illness: None. Date and time of occurrence of the adverse events: 13Dec2021, Result of the event: Active/Not resolved. Since the mixed-booster dose with Spikevax patient have been suffering from extreme muscle and joint pain above the hip, predominantly in the knees, Caves, muscle attachments, Hips and in the groin region. patient took the first dose with BioNTech - comirnaty batch no ER7812 on 20Mar2021. After 14days tested positive and 4XPCR test was positive till the beginning of May. Therefore the problems with the knee started even when hiking and climbing. Jul-Aug2021 I hiked to the (Withheld) in the Alps. But the problems started after the booster dose on 11Dec2021. Various medication have not improved my Health.  Conclusion of Previously Completed Investigation: The complaint for Pfizer BioNTech covid-19 vaccine was investigated. The investigation included reviewing the involved batch records, deviation investigation and an analysis of the complaint history for the reported lot and product type. The final scope was determined to be the associated lot(s) of the reported lot ER7812. A complaint sample was not returned. No related quality issues were identified during the investigation. There is no impact on product quality, regulatory, validation and stability. (site name withheld) concludes that the reported defect is not representative of the quality of the batch and the batch remains acceptable. The process determined that no regulatory notification was required. The reported defect could not be confirmed. No root cause or CAPA were identified as the complaint was not confirmed. PR ID of Previously Complete d Inv.