IL6 and COVID-19: IV, intravenous; JAK, Janus kinase inhibitor; IL-6, interleukin 6; NSAID, nonsteroidal anti-inflammatory drug; ICU, intensive care unit; HDU, high-dependency unit; HFNC, high-flow nasal cannula; NIV, non-invasive ventilation; RRT, renal replacement therapy; COVID-19, coronavirus disease 2019