SARS CoV-2 real-time reverse transcription-polymerase chain reaction was positive, despite the patient having received both doses of the BNT162b2 mRNA vaccine; SARS CoV-2 real-time reverse transcription-polymerase chain reaction was positive, despite the patient having received both doses of the BNT162b2 mRNA vaccine; The initial case was missing the following minimum criteria: [Unspecified product]. Upon receipt of follow-up information on [17Jan2023], this case now contains all required information to be considered valid.  This is a literature report.  An 83-year-old male patient received BNT162b2 (BNT162B2), in Feb2021 as dose 1, single (Batch/Lot number: unknown) and in Feb2021 as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history included: "Splenectomy" (unspecified if ongoing); "Acute myeloid leukemia" (unspecified if ongoing), notes: in remission. The patient's concomitant medications were not reported. The following information was reported: DRUG INEFFECTIVE (medically significant), COVID-19 (medically significant), outcome "recovering" and all described as "SARS CoV-2 real-time reverse transcription-polymerase chain reaction was positive, despite the patient having received both doses of the BNT162b2 mRNA vaccine". The patient underwent the following laboratory tests and procedures: Blood lactate dehydrogenase: 410 IU/l; Blood smear test: Revealed numerous intraerythrocytic signet ring, notes: forms (panels A-B, blue arrows; 3100 objective, total magnification 31000), consistent with babesiosis, as well as many round, basophilic inclusions, compatible with Howell-Jolly bodies (panel A, red arrow). Parasitemia was estimated at 4.5%, and no blasts were identified; Haptoglobin (normal high range 100): less than 10; Malaria antigen test: Negative for Plasmodium antigens; SARS-CoV-2 test: Positive. Therapeutic measures were taken as a result of drug ineffective, covid-19.  Clinical course: The patient with a history of splenectomy and acute myeloid leukemia (AML) in remission presented to the hospital with fever, fatigue, and upper respiratory symptoms. SARSCoV- 2 real-time reverse transcription-polymerase chain reaction was positive, despite the patient having received both doses of the BNT162b2 mRNA vaccine in February 2021. Monoclonal antibody therapy (casirivimab and imdevimab) was administered with improvement of symptoms for several days after infusion. He re-presented with recurrent fever, fatigue, and evidence of hemolysis (lactate dehydrogenase, 410 U/L; haptoglobin ,10 mg/dL [,100 mg/L]). Clinical suspicion included worsening COVID-19 infection vs relapsed AML. A blood smear revealed numerous intraerythrocytic signet ring forms (panels A-B, blue arrows; 3100 objective, total magnification 31000), consistent with babesiosis, as well as many round, basophilic inclusions, compatible with Howell-Jolly bodies (panel A, red arrow). Parasitemia was estimated at 4.5%, and no blasts were identified. He denied recent tick exposure or blood transfusion. The BinaxNOW Malaria immunochromatographic assay was negative for Plasmodium antigens. Azithromycin and atovaquone were initiated, with a subsequent decrease in parasite load and improvement of symptoms. This case highlights the importance of examining a peripheral blood smear, even when conditions other than babesiosis appear to be explanations for hemolytic anemia. Patients with asplenia and those with weakened immune systems are at increased risk for symptomatic babesiosis.; Sender's Comments: The reported COVID-19 positive after both the doses of COVID-19 immunization is considered ineffective of BNT162B2, and the Company cannot completely exclude the possible causality between the reported events and BNT162B2 administration.