Background and Purpose: Highly mutable influenza is successfully countered based on individual susceptibility and similar precision-like medicine approach should be effective against SARS-COV-2. Among predictive markers to bring precision medicine to COVID-19, circulating ACE2 has potential features being upregulated in both severe COVID-19 and predisposing comorbidities. Spike SARS-CoVs were shown to induce ADAM17-mediated shedding of enzymatic active ACE2, thus accounting for its increased activity that has also been suggested to induce positive feedback loops leading to COVID-19-like manifestations. For this reason, pre-existing ACE2 activity and inhibition of ACE2/ADAM17 zinc-metalloproteases through zinc chelating agents have been proposed to predict COVID-19 outcome before infection and to protect from COVID-19, respectively. Since most diagnostic laboratories are not equipped for enzymatic activity determination, other potential predictive markers of disease progression exploitable by diagnostic laboratories were explored. Experimental approach: Concentrations of circulating ACE2 protein and activity, albumin and zinc were investigated in healthy, diabetic (COVID-19-susceptible) and SARS-CoV-2-negative COVID-19 individuals. Key Results: ACE2 both protein levels and activity significantly increased in COVID-19 and diabetic patients. Abnormal high levels of ACE2 characterised a subgroup (16-19%) of diabetics, while COVID-19 patients were characterised by significantly higher zinc/albumin ratios, pointing to a relative increase of albumin-unbound zinc species, such as ACE2-bound and free zinc ones. Conclusions & Implications: Data on circulating ACE2 levels are in line with the hypothesis that they can drive susceptibility to COVID-19 and elevated zinc/albumin ratios support the therapeutic use of zinc chelating inhibitors of ACE2/ADAM17 zinc-metalloproteases in a targeted therapy for COVID-19.

The present work argues the involvement of zinc chelation ability of some non-steroidal anti-inflammatory drugs as an additive mechanism able to increase their efficacy against COVID-19.

The present work analyses in detail the published data on ChAdOx1 nCoV-19 vaccine and provides arguments for the involvement of anti-vector immunity and of SARS-CoV-2 variants on the efficacy of ChAdOx1 nCoV-19 vaccine. First, it is suggested that anti-vector immunity takes place as the regimen of homologous vaccination with ChAdOx1 nCoV-19 vaccine is applied and interferes with efficacy of the vaccine when the interval between prime and boost doses is less than three months. Second, longitudinal studies suggest that ChAdOx1 nCoV-19 vaccine provides sub-optimal efficacy against UK variant of SARS-CoV-2, which appears to have an increased transmissibility over the ancestral SARS-CoV-2 among vaccinated people. At the moment, ChAdOx1 nCoV-19 vaccine is able to reduce the severity of symptoms and transmissibility; however, if the vaccinated individuals do not maintain everyday preventive actions, they could turn into potential spreaders, thus accelerating the process of generation of new viral variants due to the selective pressure of immune response. Prediction and possible consequences of the SARS-CoV-2 evolution and repeated anti-SARS-CoV-2 vaccinations are discussed. Since the impact of emerging SARS-CoV-2 variants suggests that vaccines are unlikely to be effective in quickly solving the pandemic crisis, it is highlighted the need to keep searching for new and more efficacious pharmacotherapy for COVID-19, such as those targeting ACE2 and ADAM17 zinc-metalloprotease activities.