MIS-A; KAWASAKI'S DISEASE; POSITIVE SARS-COV-2 ANTI-N IGG/IGM; This spontaneous report was received from literature. A previously healthy, 25-year-old gentleman presented for 3 days of fever, headache, nausea/vomiting, and rash following travel. Vitals notable for: temperature 39.2 C, heart rate 128 b.p.m., blood pressure 130/80 mmHg. Examination revealed cervical lymphadenopathy and a pruritic, macular truncal rash. Platelet count 139 (150450k/µL), absolute lymphocyte count 0.9 (1.13.5 k/µL), creatinine 1.1 (0.71.3 mg/dL), alanine transaminase 39 (967 U/L), albumin 3.9 (3.55.0 g/dL), erythrocyte sedimentation rate >130 (05 mm/h), C-reactive protein 220 (015 mg/L), ferritin 3815 (26209 ng/mL), D-dimer 732 (less than 243 ng/mL DDU) Procalcitonin 2.87 (less than 0.50 ng/mL) and interleukin-6 171.5 (2.5 7 pg/mL). Comprehensive autoimmune, oncologic, and infectious work-up were unrevealing. aside from a positive SARS-CoV-2 anti-N IgG/IgM (indicating recent exposure). The patient denied known SARS-CoV-2 infection and received the Janssen Ad26.CoV2.S vaccine Hospitalization was complicated by persistent fever (Tmax 40.7°C), tachycardia, hypotension, and supplemental oxygen requirement. Left-sided facial droop occurred with hypotension; computed tomography angiogram showed a 1.5 mm left internal carotid artery aneurysm. On hospital day 2, strawberry tongue, injected conjunctiva, and faint rash of palms and soles appeared, meeting full Kawasaki Disease (KD) criteria.1 Cardiac evaluation was pursued: electrocardiogram was unremarkable; BNP 1788 (033.3 pg/mL); troponin peak 2.6 (less than 0.033 ng/ mL) and transthoracic echocardiogram (TTE) showed left ventricular ejection fraction (LVEF) 35% with global hypokinesis and small aneurysms of left main and proximal left anterior descending (LAD) coronary arteries. Criteria were also met for MIS-A,2 which exists with KD on the spectrum of inflammatory diseases associated with SARS-CoV-2 infection. Given this differential, the patient was treated with intravenous immunoglobulin (1 g/kg/dose for two doses), medium-dose aspirin (800 mg four times per day), methylprednisolone (12 mg/kg/day), and lisinopril with dramatic improvement and sustained normothermia. He was discharged on hospital day 10 on lisinopril, low-dose aspirin, and a prednisone taper. One week post-treatment, outpatient TTE demonstrated resolution of coronary artery aneurysms and LVEF recovery. At 6-week follow-up, lisinopril and aspirin were discontinued given normal TTE. At 6-month follow-up, TTE remained stable. This report concerned a 25 year old male of an unspecified race and ethnicity. The patient's weight, height, and medical history were not reported. The patient received covid-19 vaccine ad26.cov2.s (suspension for injection, route of admin, batch number and expiry were not reported) dose, start therapy date were not reported administered 1 in total for covid-19 prophylaxis. The batch number was not reported. Per procedure, no follow-up will be requested for this case. No concomitant medications were reported. On an unspecified date, the patient experienced mis-a (Multisystem inflammatory syndrome in adults), kawasaki's disease, and positive sars-cov-2 anti-n igg/igm and was hospitalized (date unspecified) for 10 days, date of discharge was not reported.  Laboratory data (dates unspecified) included: Absolute lymphocyte count (NR: 1.1 - 3.5) 0.9 10*3/uL, Alanine aminotransferase (NR: 9 - 67) 39 U/L, Albumin (NR: 3.5 - 5.0) 3.9 g/dL, Angiogram showed a 1.5 mm left internal carotid artery aneurysm, BNP (NR: 0 - 33.3) 1788 pg/mL, Blood pressure 130/80 mmHg, Body temperature (NR: not provided) 40.7 Cel, 39.2 Cel, C-reactive protein (NR: 0 - 15) 220 mg/dL, SARS-CoV-2 anti-N IgG/IgM Positive, Creatinine (NR: 0.7 - 1.3) 1.1 mg/dL, Electrocardiogram unremarkable, Erythrocyte sedimentation rate >130 (05 mm/h), Ferritin (NR: 26 - 209) 3815 ng/mL, Fibrin D dimer (NR: not provided) 732 ng/mL, Heart rate (NR: not provided) 128 {beats}/min, Interleukin-6 (NR: 2.5 - 7) 171.5 pg/mL, Platelet count (NR: 150 - 450) 139 10*3/uL, Procalcitonin (NR: not provided) 2.87 ng/mL, Transthoracic echocardiogram left ventricular ejection fraction (LVEF) 35% with global hypokinesis and small aneurysms of left main and proximal left anterior descending (LAD) coronary arteries, demonstrated resolution of coronary artery aneurysms and LVEF recovery, stable, and Troponin (NR: not provided) 2.6 ng/mL. Treatment medications (dates unspecified) included: acetylsalicylic acid, oxygen, methylprednisolone, and lisinopril. The action taken with covid-19 vaccine ad26.cov2.s was not applicable. The patient recovered from mis-a, and the outcome of positive sars-cov-2 anti-n igg/igm and kawasaki's disease was not reported. This report was serious (Hospitalization Caused / Prolonged).; Sender's Comments: V0: 20220903927 -covid-19 vaccine ad26.cov2.s- MIS-A , Kawasaki's disease. The case causality is considered NOT RELATED. Rationale: The concurrent  event of  positive sars-cov-2 anti-N IgG/IgM (indicating recent exposure to SARS-CoV-2) provides more plausible explanation for the events. 20220903927 -covid-19 vaccine ad26.cov2.s- Positive sars-cov-2 anti-N IgG/IgM- The event(s) has an unknown/unclear temporal relationship, is unlabeled, and has unknown scientific plausibility. There is no information on any other factors potentially associated with the event(s). Therefore, this event(s) is considered unassessable