Fanos, V.; Pintus, R.; Pintus, M. C.; Mussap, M.; Marcialis, M. A. Seven Secrets of COVID-19: Fever, ACE2 Receptors, Gut-Lung Axis, Metabolomics, Microbiomics, Probiotics, Diet. J Pediatr Neonat Individual Med 2021, 10, e100145.