Fig. 1.

Schematic, algorithmic representation of the SARS-CoV-2 variants landscape. Specific combinations of mutations and deletions are recognized. Critical deletions affect exclusively the non-RBD S1 region (ΔΗ69/ΔV70/Δ156/Δ157/ΔΥ144/ ΔL242/ΔΑ243/ΔL244) increasing virus transmission ability/infectivity affecting also negatively the immune response levels to neutralizing antibodies (decreased serum neutralization titles). D614G is the dominant and highly conserved substitution, whereas N501Y/ E484K-Q/ K417N/T/ L452R mutations are very important. del/ D614G/ E484Q combination in delta variant seems to be unique leading COVID-19 to a specific disease phenotype. A710V/V1176F/T716I/T1027/D1118H is the most important mutations in the S2 region. Omicron variant is characterized by an ‘’exotic’’ combination of many mutations, deletions and one novel insertion.