First, this is the first report to characterise free IL-18 levels in COVID-19 throughout the course of the illness; previous studies characterised either only the total IL-18 component [22, 23] which does not reflect the biologically active interleukin and may hide the true picture of inflammasome activation [13] or only analysed free IL-18 levels at admission. The gene discussed is IL18; the disease is COVID-19.