Background: Increased homocysteine serum levels (HHcy) induce Endothelium Dysfunction (ED), responsible of the activation some proinflammatory agents (“cytokine storm”), imbalance between vasodilation and vasoconstriction with vasoconstrictive prevalence, increased oxidative stress hyper-coagulability. Methods: All these events can worsen course COVID-19 in HHcy- patients, favoring evolution to...