IFNG and COVID-19: Elevated levels of IFN-γ have been observed in hospitalized patients with COVID-19 compared with healthy individuals [67], as well as in individuals with severe COVID-19 relative to mild cases in Iran [68], but no differences were detected between patients hospitalized in the intensive care unit (ICU) and those not hospitalized in the ICU [67], nor among individuals with severe and mild manifestations of COVID-19 in China [69], similar to our study.