This is a literature report for the following literature source(s): "Multisystem Inflammatory Syndrome after Breakthrough SARS-CoV-2 Infection in 2 Immunized Adolescents, Emerging Infectious Diseases. A 14-year-old male patient received BNT162b2 (BNT162B2), as dose 2, single (Batch/Lot number: unknown) for covid-19 immunisation. The patient's relevant medical history and concomitant medications were not reported. Vaccination history included: Bnt162b2 (DOSE 1), for COVID-19 immunisation. The following information was reported: MULTISYSTEM INFLAMMATORY SYNDROME (hospitalization, medically significant, life threatening), outcome "recovering". The event "multisystem inflammatory syndrome" required physician office visit. The patient underwent the following laboratory tests and procedures: Activated partial thromboplastin time (23.5-37.5): 42.9 seconds, notes: HD1; 36.5 seconds, notes: HD2; 38.9 seconds, notes: HD3; 39.4 seconds, notes: HD4; Alanine aminotransferase (normal high range 50): 221 IU/l, notes: HD1; 243 IU/l, notes: HD2; 196 IU/l, notes: HD3; 167 IU/l, notes: HD4; 195 IU/l, notes: HD5; 162 IU/l, notes: HD6; Aspartate aminotransferase (15-40): 165 IU/l, notes: HD1; 207 IU/l, notes: HD2; 131 IU/l, notes: HD3; 114 IU/l, notes: HD4; 200 IU/l, notes: HD5; 164 IU/l, notes: HD6; Blood albumin (3.5-5): 2.9 g/dl, notes: HD2; 2.8 g/dl, notes: HD3; 2.8 g/dl, notes: HD4; 3.1 g/dl, notes: HD5; 3.1 g/dl, notes: HD6; Blood creatinine (0.2-0.7): 1.2 mg/dl, notes: HD1; 1.0 mg/dl, notes: HD2; 0.9 mg/dl, notes: HD3; 0.7 mg/dl, notes: HD4; 0.8 mg/dl, notes: HD5; 0.6 mg/dl, notes: HD6; Blood culture: Negative; Blood fibrinogen (200-450): 328 mg/dl, notes: HD1; 354 mg/dl, notes: HD2; 302 mg/dl, notes: HD3; 269 mg/dl, notes: HD4; 317 mg/dl, notes: HD5; Blood immunoglobulin G: Positive; Blood lactate dehydrogenase (360-730): 1484 IU/l, notes: HD1; 1155 IU/l, notes: HD3; 928 IU/l, notes: HD4; 863 IU/l, notes: HD5; Blood sodium (137-145): 130 mmol/L, notes: HD1; 136 mmol/L, notes: HD2; 134 mmol/L, notes: HD3; 133 mmol/L, notes: HD4; 132 mmol/L, notes: HD5; 137 mmol/L, notes: HD6; Body temperature: 39.1 degree; Chest X-ray: Unremarkable; C-reactive protein (0-10): 135 mg/l, notes: HD1; 86 mg/l, notes: HD2; 64 mg/l, notes: HD3; 36 mg/l, notes: HD4; 19 mg/l, notes: HD5; 11 mg/l, notes: HD6; Culture urine: Negative; Echocardiogram: Revealed trivial pericardial effusion; Showed no effusion, notes: HD5; Showed new mild left main coronary artery enlarge, notes: ent. (Z-score + 2.7); Fibrin D dimer (normal high range 0.5): Greater than 4, notes: HD2; Greater than 4, notes: HD3; Greater than 4, notes: HD4; 3.1 ug/ml, notes: HD5; Gamma-glutamyltransferase (10-28): 126 IU/l, notes: HD1; 137 IU/l, notes: HD2; 129 IU/l, notes: HD3; 128 IU/l, notes: HD4; 136 IU/l, notes: HD5; Haemoglobin (11.8-15.8): 12.5 g/dl, notes: HD1; 13.1 g/dl, notes: HD2; 12.4 g/dl, notes: HD3; 12.2 g/dl, notes: HD4; 12.4 g/dl, notes: HD5; 10.5 g/dl, notes: HD6; Laboratory tests: hyponatremia; thrombocytopenia; lymphopenia, notes: and elevated C-reactive protein (CRP), N-terminal pro-brain natriuretic peptide (NT-proBNP), and liver function test levels; Normalized, notes: (3 weeks after hospital discharge); Lymphocyte count (1.8-4.8): 1 x10 9/l, notes: HD1; 0.6 x10 9/l, notes: HD2; 1.1 x10 9/l, notes: HD3; 1.3 x10 9/l, notes: HD4; 1.7 x10 9/l, notes: HD5; 1.8 x10 9/l, notes: HD6; Mycobacterium tuberculosis complex test: Negative; Neutrophil count (1.8-6.6): 2.4 x10 9/l, notes: HD1; 3.3 x10 9/l, notes: HD2; 1 x10 9/l, notes: HD3; 0.9 x10 9/l, notes: HD4; 1 x10 9/l, notes: HD5; 0.6 x10 9/l, notes: HD6; N-terminal prohormone brain natriuretic peptide (normal high range 125): 365 pg/mL, notes: HD1; 477 pg/mL, notes: HD2; 601 pg/mL, notes: HD3; 1020 pg/mL, notes: HD4; 212 pg/mL, notes: HD5; Platelet count (150-500): 98 x10 9/l, notes: HD1; 109 x10 9/l, notes: HD2; 188 x10 9/l, notes: HD3; 237 x10 9/l, notes: HD4; 321 x10 9/l, notes: HD5; 362 x10 9/l, notes: HD6; Polymerase chain reaction: Negative; Negative; Negative; Prothrombin time (11.5-15.0): 14 seconds, notes: HD1; 12.6 seconds, notes: HD2; 13.5 seconds, notes: HD3; 13.7 seconds, notes: HD4; 14.1 seconds, notes: HD5; 13.5 seconds, notes: HD6; Red blood cell sedimentation rate (normal high range 15): 6, notes: (mm/h) HD2; 7, notes: (mm/h) HD3; 23, notes: (mm/h) HD4; 24, notes: (mm/h) HD5; 25, notes: (mm/h) HD6; SARS-CoV-2 antibody test: Positive; Positive; SARS-CoV-2 test: Positive; Negative; Serum ferritin (6-464): 750 ng/ml, notes: HD1; 576 ng/ml, notes: HD3; 626 ng/ml, notes: HD4; 754 ng/ml, notes: HD5; 578 ng/ml, notes: HD6; Specialist consultation: ongoing fatigue 6 weeks after hospital discharge; Troponin I (normal high range 0.03): 0.03 ng/ml, notes: HD1; 0.04 ng/ml, notes: HD2; 0.05 ng/ml, notes: HD3; 0.03 ng/ml, notes: HD4; 0.02 ng/ml, notes: HD5; Ultrasound abdomen: Unremarkable; Viral test: Consistent with prior infection; White blood cell count (5.2-9.7): 3.6 x10 9/l, notes: HD1; 4.1 x10 9/l, notes: HD2; 2.3 x10 9/l, notes: HD3; 2.6 x10 9/l, notes: HD4; 3.1 x10 9/l, notes: HD5; 2.7 x10 9/l, notes: HD6. Therapeutic measures were taken as a result of multisystem inflammatory syndrome. Clinical course was as follows: headache and myalgia developed in a healthy 14-year-old boy (day 1 of illness); by day 7, fever, abdominal pain, diarrhea, emesis, bloodshot eyes, red cracked lips, and rash had also developed. On day 10, he was brought for treatment to the emergency department and admitted to a quaternary-care pediatric hospital. Three months earlier, he completed the Pfizer-BioNTech 2-dose COVID-19 vaccine series. One month later, he experienced 3 days of coughing and congestion and tested positive by PCR for SARS-CoV-2 infection, from which he recovered. At hospital admission, examination noted sickly appearance, fever (39.1°C), tachycardia, rash, conjunctivitis, cracked lips, and abdominal tenderness. Laboratory testing revealed hyponatremia; thrombocytopenia; lymphopenia; and elevated C-reactive protein (CRP), N-terminal pro-brain natriuretic peptide (NT-proBNP), and liver function test levels. Echocardiogram revealed trivial pericardial effusion. Abdominal ultrasound and chest radiograph results were unremarkable. SARS-CoV-2 spike and nucleocapsid IgG results were positive. Other infectious condition test results were negative. On the patient first day of hospitalization, the infectious diseases section was consulted, and the Authors determined that the patient illness met Centers for Disease Control and Prevention MIS-C criteria. The next day, he received infliximab (10 mg/kg), followed by intravenous immunoglobulin. Rash, headache, conjunctivitis, and CRP improved; however, fever, malaise, and nausea persisted, and cardiac markers rose, prompting a second infliximab dose on hospitalization day 3. His fever subsided, and signs, symptoms, and laboratory results improved. On hospitalization day 5, echocardiogram showed no effusion; he was discharged the next day. Infectious diseases follow-up 3 weeks after hospital discharge revealed fatigue and occasional mild abdominal pain but normalized laboratory results. Cardiology follow-up 6 weeks after hospital discharge revealed ongoing fatigue. An echocardiogram showed new mild left main coronary artery enlargement (Z-score +2.7). They planned no interventions beyond interval outpatient monitoring. Sender's Comments: As there is limited information in the case provided, the causal association between the reported events and the suspect drug cannot be excluded. The case will be reassessed once new information is available. The impact of this report on the benefit/risk profile of the Pfizer drug is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees, and Investigators, as appropriate. Linked Report(s): US-PFIZER INC-202201151203 Same article/drug/event and different patient.