ACE2 and COVID-19: The existence of this type of antibody generated in vaccinees or vaccinated patients with COVID-19 (Figure 9), which could alter the strength of trimeric Spike-ACE2 interaction, might explain the above significantly higher (up to 2.18) or lower (up to 3.17) titer fold change of cPass to sVNA in vaccinees and vaccinated patients with COVID–19, respectively (Table 2).