A dysfunction (e.g. over-reactivity) of RAS, together with hypovitaminosis D, is likely associated with some of the various renal, cardiac, vascular and immune outcomes that might be observed in COVID-19 patients, including the cytokine storm (i.e. unopposed hyperactive immune reaction generating both pro-inflammatory and anti-inflammatory cytokines) and consequent lethal acute respiratory distress syndrome [1, 7].