COVID 19 Treatment; COVID 19 Treatment; This is a spontaneous report received from a contactable reporter(s) (Nurse) from product quality group.  A 44-year-old male patient received BNT162b2 (BNT162B2), on 17Dec2020 as dose 1, single (Lot number: EK5730) intramuscular, on 07Jan2021 as dose 2, single (Batch/Lot number: unknown) and on 04Oct2021 as dose 3,single (Lot number: 30155BA) at the age of 44 years intramuscular for covid-19 immunisation. The patient had no relevant medical history. There were no concomitant medications. The following information was reported: DRUG INEFFECTIVE (medically significant), COVID-19 (medically significant), outcome "not recovered" and all described as "COVID 19 Treatment". The patient underwent the following laboratory tests and procedures: SARS-CoV-2 antibody test: Unknown result. Therapeutic measures were taken as a result of drug ineffective, covid-19.  Clinical course: Patient had not taken any other medications in two weeks. Antiviral details includes Product: COVID 19 Treatment: Brand of Paxlovid, Treatment start date on 18May2022, Treatment stop date on 23May2022, Indication: Treatment of COVID-19 , Administrator route: Oral. Completed Paxlovid on 22May2022 and developed rebound symptoms on 23May2022 (congestion, fever, chills, body aches, fatigue). It was unknown if patient had any allergies. There was no medical history.   Investigation conclusion: Product-Description (CR): COMPOUND BNT162 COVID-19 VACCINE SUSPENSION FOR INTRAMUSCULAR 2ML MULTIPLE DOSE VIAL X 1.  Lot numbers (CR): 30155BA Conclusion of Previously Completed Investigation: The complaint for a lack of effect in a vial of PFIZERBIONTECH COVID-19 VACCINE 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 per-formulated bulk, and is manufactured, labeled, and packaged by Pfizer (site name withheld). The final scope was determined to be lot number 30155BA. No quality issues were identified during the investigation. There is no impact on product quality. An was not issued for the complaint. No regulatory notifications were held because of this complaint. The complaint condition of lack of effect was not confirmed, therefore the root cause cannot be attributed to the manufacture or vendor processes as incoming quality component testing and all analytical tests performed at the time of lot release confirmed that the batch met potency specifications. 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 to any lot being released to the market.  Lot-number (CR): EK5730 Conclusion of Previously Completed Investigation: The complaint for lack of effect of the PFIZER- BIONTECH COVID-19 VACCINE lot EK5730 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 EK5730, fill lot EK3313, and the formulated drug product lot EK3312. 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. When more than one investigation is found in the family, the Conclusion field could result in repeating rows for the CR in the table. If the Conclusion is blank in the table above, then the investigation record is likely an Offline Contractor Investigation and the conclusion must be obtained directly from the child investigation record(s) of the linked Complaint Record.  The information on the batch/lot number for BNT162b2 has been requested and will be submitted if and when received.; Sender's Comments: Based on the available information and the known product safety profile a causal relationship between the reported events, COVID 19, Drug Ineffective and BNT162B2 is considered possible.