This is a spontaneous report received from contactable reporter(s) (Consumer or other non HCP) from product quality group. The reporter is the patient. A 53-year-old female patient (not pregnant) received BNT162b2 (BNT162B2), on 06Mar2021 as dose 1, single (Lot number: EN6199), on 27Mar2021 as dose 2, single (Lot number: EP6534) and on 27Sep2021 as dose 3 (booster), single (Lot number: 30145BA) at the age of 53 years for Covid-19 immunisation. The patient's relevant medical history included: "Post-operative thyroid cancer" (unspecified if ongoing); "skin cancer" (unspecified if ongoing); "GERD" (unspecified if ongoing). Concomitant medication(s) included: LEVOTHYROXINE; OMEPRAZOLE. Past drug history included: Morphine, reaction(s): "Drug allergy: Morphine"; Azithromycin, reaction(s): "Drug allergy: Azithromycin". The following information was reported: VACCINATION FAILURE (medically significant), COVID-19 (medically significant), outcome "not recovered" and all described as "Treatment of COVID-19". The patient underwent the following laboratory tests and procedures: SARS-CoV-2 test: Positive, notes: COVID-19 symptoms returned a few days after I finished the course of Paxlovid. I am still testing positive at home several days after finishing the course. Therapeutic measures were taken as a result of Covid-19. Clinical course: COVID-19 symptoms returned a few days after the patient finished the course of Paxlovid. The patient still testing positive at home several days after finishing the course. Conclusion of Previously Completed Investigation (FCI/SI/OffCI): The complaint for a Lack of effect of the PFIZER BIONTECH COVID-19 VACCINE lot 30145BA was investigated. The investigation included reviewing incoming quality and manufacturing batch records, deviation investigations, an analysis of the complaint history for the reported lot and product type and final release assay testing. This product is received as preformulated bulk, and is manufactured, labeled and packaged by Pfizer (site name withheld). The final scope was determined to be lot 30145BA. No quality issues were identified during the investigation. There is no impact on product quality. An RA was not issued for the complaint. No regulatory notification or AQRTs were held as a result of this complaint. The compliant condition of lack of effect was not confirmed, therefore the root cause cannot be attributed to manufacture or vendor processes. The root cause was not determined to be manufacture or vendor related as incoming quality component testing, bulk release testing and certificate of analysis indicates all product testing was determined to be acceptable at time of release. No corrective or preventative actions are required as the complaint condition was not determined to be manufacture or vendor related and there are quality systems in place to detect defects prior any lot being released to the market. No further investigation required. Conclusion of Previously Completed Investigation (FCI/SI/OffCI): The complaint for lack of effect of the PFIZER BIONTECH COVID-19 VACCINE lot EN6199 was investigated. The investigation included a review of manufacturing and packaging batch records, deviation investigations, and an analysis of complaint history for the reported lot. The final scope included the reported finished goods lot EN6199, fill lot EN5331, and the formulated drug product lot EN5320. A complaint sample was not returned, and photographs were not received. No related quality issues were identified during the investigation. There is no impact to product quality. No root cause or corrective/preventative actions were identified as the complaint was not confirmed. All release testing performed prior to the release of the reported batch was within specifications. No Follow-up attempts are possible. No further information is expected.