NGF and COVID-19: Thus, we determined the levels of growth hormone (GH), insulin-like growth factor-1(IGF-1), insulin, brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), oxytocin, acylated ghrelin (AG), platelet-derived growth factor (PDGF), fibroblast growth factor-1 (FGF-1), and transforming growth factor-beta (TGF-β) six-months after the acute phase and fifteen months after recovery from severe COVID-19.