During the COVID-19 pandemic, some patients developed a severe fungal infection called mucormycosis alongside their coronavirus infection. This study found that 63 COVID-19 patients in Iran developed mucormycosis, which primarily affected the sinuses and brain. The researchers identified that a fungus called Rhizopus arrhizus caused most infections, and patients who received corticosteroids (used to treat severe COVID-19) had a higher risk, especially those who developed diabetes from the steroids.