Tested positive for Covid virus, after being fully vaccinated.; Tested positive for Covid virus, after being fully vaccinated.; This is a spontaneous report from contactable consumer. This consumer reported similar events for 37 patients. This report is for 6th of 37 patient. This consumer reported for a female patient.  A female patient of an unspecified age received BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, formulation: Solution for injection, Batch/Lot Number: EN5318; Expiration Date: 31May2021), dose 1 via an unspecified route of administration on 23Jan2021 as dose 1, single, and BNT162B2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, formulation: Solution for injection, Batch/Lot Number: EL9266; Expiration Date: not reported), dose 2 via an unspecified route of administration on 12Feb2021 as dose 2,single for COVID-19 immunization. The patient medical history and concomitant medications were not reported. It was reported that the caller stated about the Pfizer Covid 19 vaccine, the caller reported 37 breakthrough cases, for fully vaccinated patients testing positive for Covid. The Covid positive were defined as having both vaccines and testing positive for Covid longer than two weeks after both doses on13May2021. The caller stated they were monitoring and tracking the vaccine breakthrough cases in their area and the caller had some concerns regarding one specific lot number that 15% of their breakthrough cases had received. The lot number provided was EN5318. The caller at the time, did not have the NDC or expiration date, however, was going to work on pulling patient information so that she would be able to have this information available to provide upon transfer. The Caller stated, re-clarified later in report, she had 37 patients with partial identifiers. The Caller stated she cannot provide some identifying details and that she would need to check with her legal department first. The caller provided the details she was allowed to identify. The Caller stated she can provide, age, gender, BMI, medical conditions, if reported, and date they tested positive for Covid, and the type of Covid test utilized. The Caller later stated, she cannot provide the zip code. Upon follow-up on 20Aug2021, a Product Quality Complaint was received from a Product Quality Complaint Group for LOT EN5318. The conclusion included the complaint for lack of effect of the PFIZER-BIONTECH COVID-19 VACCINE INJECTABLE lot EN5318 was investigated. The investigation included reviewing manufacturing and packaging batch records, deviation investigations, and an analysis of complaint history for the reported lot. The final scope was determined to be the reported finished goods lot EN5318, fill lot EN5317, and the formulated drug product lot EN5316. A complaint sample was not returned. No related quality issues were identified during the investigation. There is no impact on product quality. No root cause or CAPA were identified as the complaint was not confirmed. All release testing performed prior to the release of the reported batch was within specifications. Further a brief Complaint Description: PFIZER-BIONTECH COVID-19 VACCINE INJECTABLE - EN6200- Lack of Effect was received, the complaint was agreed with the site assignment, investigation decision, classification, sub-classification, and priority. The reported lot number was valid, and an investigation will be performed. The patient underwent lab tests and procedures which included PCR Covid test: positive on 13May2021. Outcome of the event tested positive for Covid virus, after being fully vaccinated was reported as unknown at this time of the report.   Follow-up attempts are completed. No further information is expected.; Sender's Comments: Linked Report(s) : US-PFIZER INC-202101075254 same reporter, AE and drug, different patient