Multisystem inflammation syndrome; This literature-non-study case was reported in a literature article and describes the occurrence of MULTISYSTEM INFLAMMATORY SYNDROME (Multisystem inflammation syndrome) in a 58-year-old male patient who received mRNA-1273 (Spikevax) for COVID-19 prophylaxis.   LITERATURE REFERENCE:     Concurrent medical conditions included Obesity and Hypertension.    On an unknown date, the patient received second dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form. On an unknown date, the patient experienced MULTISYSTEM INFLAMMATORY SYNDROME (Multisystem inflammation syndrome) (seriousness criteria hospitalization, medically significant and life threatening). The patient was treated with PREDNISONE for Multisystem inflammatory syndrome, at an unspecified dose and frequency and OXYGEN at an unspecified dose and frequency. At the time of the report, MULTISYSTEM INFLAMMATORY SYNDROME (Multisystem inflammation syndrome) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Alanine aminotransferase: elevated. On an unknown date, Angiocardiogram: Type 2 NSTEMI was diagnosed after coronary angiogram showed no stenosis or aneurysm.. On an unknown date, Aspartate aminotransferase: elevated. On an unknown date, Biopsy kidney: Renal biopsy showed acute interstitial nephritis likely from NSAID use and acute tubular necrosis (ATN). On an unknown date, Blood bilirubin: elevated. On an unknown date, C-reactive protein: elevated. On an unknown date, CSF test: Brain imaging and CSF examination were unremarkable.. On an unknown date, Computerised tomogram: Thoracic CTA ruled out pulmonary embolism with no pulmonary infiltrates.. On an unknown date, Magnetic resonance cholangiopancreatography: Biliary obstruction and liver disease were excluded by MRCP and serology. On an unknown date, SARS-CoV-2 antibody test: (Positive) Nucleocapsid antibody for COVID-19 was positive suggestive of past infection. On an unknown date, SARS-CoV-2 test: Negative. On an unknown date, Serum ferritin: elevated. On an unknown date, Troponin: elevated.     For mRNA-1273 (Spikevax) (Unknown), the reporter considered MULTISYSTEM INFLAMMATORY SYNDROME (Multisystem inflammation syndrome) to be related.    Patient presented with a seven-day history of headache, nausea, myalgias and one day of fever, chills, sweats, and diarrhea following the second dose of COVID-19 mRNA vaccine. He was anxious, encephalopathic and had an erythematous blanching rash on his back.  Patient had mild splenomegaly, pancytopenia, and acute kidney injury. Comprehensive workup was negative for infectious etiology and vasculitis. Patient's skin rash was thought to be nonspecific and biopsy wasn't performed.  Post extubation, his persistent encephalopathy is slowly improving. After ruling out all potential differential diagnosis including infectious, vasculitis, thrombotic, and immune etiology, a diagnosis of MIS secondary to mRNA Covid-19 vaccination was made and reported to the CDC.  Company comment: This literature non-study case concerns a 58-year-old male patient, with relevant medical conditions of obesity and hypertension, who experienced the unexpected and serious (due to life-threatening, hospitalization and medically significant) AESI of Multisystem inflammatory syndrome. Patient presented with a 7-day history of headache, nausea, myalgias and 1 day of fever, chills, sweats and diarrhea, following mRNA-1273 vaccine, administered as second dose within COVID-19 vaccination schedule. He was anxious, encephalopathic and had an erythematous blanching rash on his back. He had elevated C-reactive protein, ferritin, troponin, bilirubin, AST, ALT, mild splenomegaly, pancytopenia and acute kidney injury. He required intubation for encephalopathy and developed post-sedation hypotension. His comprehensive workup was negative for infectious etiology and vasculitis. Blood smear didn´t reveal schistocytes. Nucleocapsid antibody for COVID-19 was positive suggestive of past infection, while PCR test was negative. Thoracic CTA was normal. Type 2 non-ST-elevation myocardial infarction was diagnosed after coronary angiogram showed no stenosis or aneurysm. Serology and magnetic resonance cholangiopancreatography excluded biliary obstruction. Renal biopsy showed acute interstitial nephritis likely from non-steroidal anti-inflammatory drugs, and acute tubular necrosis. Renal function improved after a prednisone course. Brain imaging and cerebrospinal fluid examination were unremarkable. Following a period of critical organ support in the intensive care unit and gradual in-hospital convalescence, patient made a full recovery. Underlying obesity and hypertension could be contributory factors for patient´s evolution. Suggestive past infection of COVID-19 could be a confounding factor for Multisystem inflammatory syndrome. The benefit-risk relationship of mRNA-1273 is not affected by this report.   Most recent FOLLOW-UP information incorporated above includes: On 24-Oct-2022: Follow up received by safety on 26-OCT-2022 has Email with abstract that contains significant information: New literature citation and event details updated.; Sender's Comments: This literature non-study case concerns a 58-year-old male patient, with relevant medical conditions of obesity and hypertension, who experienced the unexpected and serious (due to life-threatening, hospitalization and medically significant) AESI of Multisystem inflammatory syndrome. Patient presented with a 7-day history of headache, nausea, myalgias and 1 day of fever, chills, sweats and diarrhea, following mRNA-1273 vaccine, administered as second dose within COVID-19 vaccination schedule. He was anxious, encephalopathic and had an erythematous blanching rash on his back. He had elevated C-reactive protein, ferritin, troponin, bilirubin, AST, ALT, mild splenomegaly, pancytopenia and acute kidney injury. He required intubation for encephalopathy and developed post-sedation hypotension. His comprehensive workup was negative for infectious etiology and vasculitis. Blood smear didn´t reveal schistocytes. Nucleocapsid antibody for COVID-19 was positive suggestive of past infection, while PCR test was negative. Thoracic CTA was normal. Type 2 non-ST-elevation myocardial infarction was diagnosed after coronary angiogram showed no stenosis or aneurysm. Serology and magnetic resonance cholangiopancreatography excluded biliary obstruction. Renal biopsy showed acute interstitial nephritis likely from non-steroidal anti-inflammatory drugs, and acute tubular necrosis. Renal function improved after a prednisone course. Brain imaging and cerebrospinal fluid examination were unremarkable. Following a period of critical organ support in the intensive care unit and gradual in-hospital convalescence, patient made a full recovery. Underlying obesity and hypertension could be contributory factors for patient´s evolution. Suggestive past infection of COVID-19 could be a confounding factor for Multisystem inflammatory syndrome. The benefit-risk relationship of mRNA-1273 is not affected by this report.