According to the research mentioned above, the mechanism that viral proteins infect red blood cells may be clarified. Through the tryptophan-threonine-rich Plasmodium antigen (TryThrA), the S protein, ORF3a proteins invaded red blood cells. S protein TryThrA exhibited C1q activity, whereas ORF3a TryThrA exhibited EBA-175 activity. Through the C1q domain, the S protein was bound to the complement receptor 1 on the red blood cell membrane. ORF3a EBA-175 domains were bound to glycophorin A on the red blood cell membrane. S protein, ORF3a are all bound to band 4.1 and anchor to the skeleton of the red blood cell membrane. Through the MACPF domain, the S protein creates a fusion hole in the red blood cell membrane, injecting viral genetic material into the red blood cell. Through the ion channel constructed by the S protein, the SARS-COV-2 virus injected calcium ions from the virus to the membrane fusion area . By using thiol-activated cytolysin, ORF3a created a pore in the erythrocyte membrane. These pores contained ryanodine receptors activity and were capable of releasing calcium ions from within red blood cells. Calcium ion was a factor in blood clotting. As a result, the entry of viral proteins into the red blood cell would not result in a significant hemolytic reaction. Besides, EBA-175 was associated with blood type A. The Knops blood group system was based on a glycoprotein antigen (i.e., CR1 or CD35, complex immune receptor). So blood cells from people with blood type A and Knops were susceptible to infection by the SARS-COV-2 virus.