LEP and obesity due to melanocortin 4 receptor deficiency: It is postulated that the mechanisms underlying the relationship between the worst course of COVID-19 and obesity are universal mechanisms for various infections, including influenza A, mainly higher levels of circulating leptin and pro-inflammatory cytokines, reduced macrophage activation, both T cell and B cell response associated with the obesity-related chronic inflammatory state and increased viral spread to the alveolar region of the lungs [40].