M ultisystem infl ammatory syndrome (MIS) in children (MIS-C) and adults (MIS-A) are febrile syndromes with elevated infl ammatory markers that usually manifest 2-6 weeks after a severe acute respiratory syndrome 2 (SARS-CoV-2) infection (1-3). The Brighton Collaboration Case Defi nition for MIS-C/A was recently published to be used in the evaluation of patients after SARS-CoV-2 immunization (3); some scientists are concerned that vaccination against SARS-CoV-2 can trigger MIS-C/A. We report 6 cases of MIS from a large integrated health system in Southern California, USA; 3 of those patients received SARS-CoV-2 vaccination shortly before seeking care for MIS. All 6 patients met the Brighton Collaboration Level 1 of diagnostic certainty for a defi nitive case and had MIS illness onset between January 15-February 15, 2021. The Chief Compliance Offi cer for the Southern California Permanente Medical Group reviewed this case series and confi rmed that it was compliant with the Health Insurance Portability and Accountability Act for publication.
The StudyPatient 1 was a 20-year-old Hispanic woman who sought care for 3 days of a diffuse body rash, tac-tile fever, sore throat, mild neck discomfort, and fatigue. There was no cough, congestion, headache, or abdominal pain. She had vomiting and diarrhea, which had subsided 8 days before admission. She received her fi rst dose of SARS-CoV-2 vaccine 15 days before admission. She had no known coronavirus disease (COVID-19) exposure but was SARS-CoV-2 PCR and nucleocapsid IgG positive. She was hypotensive at arrival to the emergency department, requiring inotropic support. She had elevated troponin and brain natriuretic peptide (BNP) with a left ventricular ejection fraction initially mildly reduced at 45% but 30%-35% the following day. She responded well to therapy with intravenous immunoglobulin (IVIG) and methylprednisolone (Table 1).Patient 2 was a 40-year-old Hispanic man who sought care after 6 days of episodic fevers up to 101.7°F. Associated symptoms included dyspnea on exertion, headache, neck pain, lethargy, abdominal pain, and diarrhea. No chest pain was present. He had a history of SARS-CoV-2 vaccination and laboratory-confi rmed mild to moderate COVID-19, both within 48 days before seeking care (Figure). His exam was notable for sweats, diffuse abdominal pain on palpation, tachycardia, and tachypnea. Patient 2 fulfi lled Brighton Level 1 criteria for MIS-A with documented fevers, gastrointestinal and neurologic symptoms, elevated infl ammatory and cardiac markers, and electrocardiogram changes that were concerning for myocarditis (3). He responded well to treatment with dexamethasone (Table 1).Patient 3 was an 18-year-old Asian American man who sought care at the emergency department with a history of 3 days of fever as high as 104°F with headache, vomiting, diarrhea, and abdominal cramping (Figure). He denied any upper respiratory symptoms. He had a history of a laboratoryconfi rmed COVID-19 infection 6 weeks before the onset of symptoms and received the fi rst d...