In the scenario of SARS-CoV-2 vaccination or infection, the idiotype antibody would be against the spike protein (anti-spike antibody, or Ab1), and the anti-idiotype antibody would be against the anti-spike protein (anti-anti-spike protein, or Ab2), but due to being a mirror of the idiotype antibody, some paratopes could have the ability to bind the spike protein target receptor, ACE2 (anti-ACE2 antibody) (graphical abstract). This evidence concerns the gene ACE2 and infection.