This spontaneous report received from a patient via Regulatory Authority the Vaccine Adverse Event Reporting System (VAERS) concerned a 46 year old white non Hispanic or Latino male via literature: Persistence of Ad26.COV2.S-associated VITT and specific detection of VITT antibodies. Local Journal of Hematology 2022. The objective of this study was to study COVID-19 vaccinated individuals develop anti-platelet factor 4 (PF4) antibodies that cause thrombocytopenia and thrombotic complications, a syndrome referred to as vaccine induced immune thrombotic thrombocytopenia (VITT). The patient's height and weight were not reported. The patient's pre-existing medical conditions included he had no known allergies to medications, food or other products. He had no history of cellulitis, gout, deep vein thrombosis (DVT) or pulmonary embolism (PE). He had no photophobia, no altered mental status, no ataxia, no meningismus. He had no chest pain or shortness of breath, had no cough and no other complaint. The patient received Covid-19 vaccine ad26.cov2.s (suspension for injection, intramuscular, batch number: 201A21A and expiry: unknown) dose was not reported, 01 total administered in arm on 08-APR-2021 for prophylactic vaccination. Concomitant medications included Singulair (montelukast sodium) and Ventolin (salbutamol). On 18-APR-2021, the patient experienced pain in right posterior thigh, popliteal fossa and calf which appeared on contralateral side/pain and tenderness over left calf extending down into ankle and dorsum of foot/body aches. On 19-APR-2021, the patient experienced deep vein thrombosis, pulmonary embolism, thrombocytopenia, peripheral swelling, vaccination complication, erythema and warmth, generalized chest discomfort, chills, fatigue, fever and headache (throughout this course he had a significant headache which was described as bitemporal, positional, and worse when bent over and better when upright and it was mild to moderate). Laboratory data included: Blood electrolytes (NR: not provided) Within normal ranges, complete blood count (CBC) (NR: not provided) Not Reported, Electrocardiogram (ECG) (NR: not provided) Normal sinus rhythm, Fibrin D Dimer abnormal (NR: not provided) 28980 FEU, Fibrinogen (NR: not provided) 200 mg/dL, Hematocrit (NR: not provided) 41.1 %, Hemoglobin (NR: not provided) 14.7 g/dL, Heparin-induced thrombocytopenia test (NR: not provided) Positive, Immunology test (NR: not provided) Not Reported, Platelet count (NR: not provided) 54 10*9/L, and White blood cells (WBC) (NR: not provided) 12.3 10*9/L. On 22-APR-2021, Laboratory data included: Diagnostic ultrasound (NR: not provided) Negative bilateral lower extremity ultrasound, enzyme-linked immunoassay (ELISA) (NR: not provided) 3.016 OD, Head Computerised tomogram (CT) (NR: not provided) non-contrast; no results provided, and Heparin-induced thrombocytopenia test (NR: not provided) Negative. On 24-APR-2021, Laboratory data included: Angiogram (NR: not provided) chest; bilateral PE, possible lingular infiltrate vs infarct, Brain natriuretic peptide (NR: not provided) negative, Comprehensive metabolic panel (NR: not provided) Glucose of 121, otherwise negative, Diagnostic ultrasound (NR: not provided) left DVT from popliteal vein through ankle, Glucose (NR: not provided) 121, 138, 138, INR (NR: not provided) 1.3, Platelet count (NR: not provided) thrombocytopenia with count 25, Platelet factor 4 (NR: not provided) 2.407 (Ag detected by ELISA), Prothrombin time (NR: not provided) 14.7, Troponin (NR: not provided) undetectable and Venogram (NR: not provided) no acute thrombus or other process noted. On an unspecified date, the patient experienced vaccine induced thrombotic thrombocytopenia. Laboratory data (dates unspecified) included: Serotonin release assay (NR: not provided) Not Reported. Treatment medications (dates unspecified) included: bivalirudin, prednisone and apixaban with direct oral anticoagulants. He was also given high dose intravenous immunoglobulin G. On an unspecified date, the patient was hospitalized. The number of days hospitalized was 3 days and the discharge information was not reported. He had visited the physician's office and emergency room. The action taken With covid-19 vaccine ad26.cov2.s was not applicable. The patient was recovering from platelet count decreased, had not recovered from deep vein thrombosis, headache, heparin-induced thrombocytopenia test positive, peripheral swelling, pulmonary embolism, vaccination complication, white blood cell count increased, anticoagulant therapy, blood electrolytes normal, blood fibrinogen normal, electrocardiogram normal, fibrin d dimer increased, full blood count, haematocrit normal, haemoglobin normal, immunoglobulin therapy, and immunology test, and the outcome of thrombocytopenia, pain in right posterior thigh, popliteal fossa and calf which appeared on contralateral side/pain and tenderness over left calf extending down into ankle and dorsum of foot/body aches, erythema and warmth, chills, fatigue, fever, generalized chest discomfort and vaccine induced thrombotic thrombocytopenia was not reported. The authors emphasized that the associated VITT antibodies persisted for greater than 5 months in platelet factor 4 (PF4) polyanion enzyme linked immunosorbent assays (ELISA) while the PEA became negative earlier. Thus, it was concluded that the patients with VITT demonstrate long term ELISA positivity, although functional assays become seronegative earlier during the course of recovery. The data suggest that the uncomplexed PF4 ELISA is sensitive and significantly more specific for the detection of VITT than currently available tests. This report was serious (Hospitalization Caused / Prolonged). This case is a duplicate of 20220237634. This case, from the same reporter is linked to 20210448310, 20210444498, 20210415297, 20220249472, 20220249398, 20220249417, 20220249503 and 20220249430. Following receipt of additional information from other health professional via literature on 10-MAR-2022. It was determined that nullification and deletion was required for 20220237634 as it was duplicate of 20210515201. All relevant information regarding 20220237634 will be submitted under 20210515201. The following information was updated and incorporated into the case narrative: Reporters, events (vaccine induced thrombotic thrombocytopenia), lab data (Immunology test, Heparin-induced thrombocytopenia test, PF4 polyanion enzyme linked immunosorbent assays, serotonin release assay), treatment medications was added. Upon review following information was amended: Patient's medical history, events (erythema and warmth, generalized chest discomfort, chills, fatigue and fever), lab dates were updated. Sender's Comments: V3.The version updates update: Reporter, events (vaccine induced thrombotic thrombocytopenia),lab data, VAERS ID, patients medical history, MAC updated. 20210515201-Covid-19 vaccine ad26.cov2.s -vaccine induced thrombotic thrombocytopenia. This event(s) is labeled per RSI and is therefore considered potentially related. This spontaneous report concerns a 46- year- old white male (non-Hispanic/Latino) who was hospitalized for deep vein thrombosis(DVT) & pulmonary embolism(PE) 16 days after COVID-19 Ad26.COV2.S vaccine. The patient denies prior history of cellulitis, gout, DVT, PE, and allergies. Symptoms reported were right leg swelling and bi-temporal headache that prompted urgent care consultation. Emergency department(ED) consultation 16 days after vaccination, where it was found that a few days prior there was some transient pain in his right posterior thigh, popliteal fossa & calf that extended to the ankle and dorsum of the foot; that also appeared on the right. The patient complained of chills, fatigue, fever(unknown temperature) & body aches; vague and intermittent generalized chest discomfort. The patient was diagnosed with left lower extremity DVT & bilateral PE & was transferred to a hospital for management including anticoagulation with a direct thrombin inhibitor and intravenous immune globulin (IVIG).Laboratory/diagnostic test results: platelet count (PC) 25 and (54 on repeat);INR 1.3;PT 14.7;PF-4 Assay 2.407(ELISA);HIT ELISA 3.016 OD;DVT on left from popliteal vein through ankle on ultrasound; bilateral pulmonary emboli, possible lingular infiltrate versus infarct on chest CTA chest; no acute thrombus noted on head CT venogram. The patient had not recovered. Based on the evolving knowledge of Thrombosis with Thrombocytopenia Syndrome (TTS, per definition from Brighton Collaboration - BC) & considering the low platelet count and temporal relationship to vaccination (BC Criteria level 2), the events are assessed to have a plausible relationship with vaccination.