A. COVID-19 vaccines induce higher levels and a broader range of neutralizing antibodies to the receptor binding domain (RBD) of the spike protein than does natural infection. Vaccine-induced antibodies are less likely to be affected by changes in the RBD seen in the current SARS-CoV-2 variants, and are therefore more likely to be more effective against variants.
➡️ TL;DR. The receptor binding domain (RBD) of the SARS-CoV-2 spike protein binds to ACE2 receptors on human cells, allowing the virus to enter. A robust neutralizing antibody response against the RBD is critical for protection against infection. While both natural infection and COVID-19 vaccines induce neutralizing antibodies to RBD, COVID-19 vaccines induce a much LARGER VARIETY of neutralizing antibodies to RBD than does natural infection. What does this mean for immunity to SARS-CoV-2 infection? Vaccine-induced antibodies can bind to MANY more places on the RBD than natural infection-induced antibodies can and may therefore be more effective in blocking the virus (and its variants) from entering human cells.