AGT and acute respiratory failure: So far, we cannot conclude whether or not having a ‘silent phase’ matters for the Ang II-AT1R-ROS-HIF axis following SARS-CoV-2 infection, but a clinical comparison of survival/mortality in patients with silent hypoxia (phenotype I) and patients with symptomatic hypoxia and clinical signs of acute respiratory failure (phenotype II) indicated higher ICU mortality (29.2% vs. 18.8%, p < 0.014) and in-hospital mortality (32.5% vs. 18.8%, p < 0.002) in phenotype II (however, a multivariate analysis showed that the cause of silent hypoxia was not clearly identified) [157].