Figure 2.

Schematic representation of antibody action and antibody dependent enhancement (ADE) to viral infection. (a) Antibodies generated after a few days of viral infection or successful vaccination, which in turn neutralize the viruses, enabling protection from further infection. (b) Secondary infection or infection after vaccination with a different viral strain causes failure of complete neutralization by the previously existing antibody. However, due to sharing some antigen similarities, partial neutralization may accelerate viral internalization by antibody-binding Fc receptors. Although nucleic-acid-based COVID-19 vaccines have been successfully approved and have shown no ADE complications in trials, including non-human primate animal studies, vaccinated individuals should be monitored across time