A patient with systemic mastocytosis had a delayed but severe mast cell activation (MCA) attack after getting an mRNA COVID booster—think fever, rash, and crazy-high cytokine levels. He ended up in the hospital and needed some serious meds, including tocilizumab, to calm things down. The wild part? He had a similar reaction a year later after actually catching COVID. Doctors say tracking IL-6 levels could help treat others with SM during these scary episodes. #MedicalMystery #COVID19 #VaccineSideEffects #SystemicMastocytosis #HealthNews #Health