NOS3 and COVID-19: The NOS3 genetic polymorphisms T(-786)C, 27-bp VNTR 4b/a, and G894T influence the NOS3 expression and/or activity; thus, considering the NOS3 role in the immune system defense against COVID-19, genetic polymorphisms may be associated with the course and severity of COVID-19 [12,14,19,20,21,22,23,40,41].