IFITM3 and COVID-19: In addition, the naturally occurring single nucleotide polymorphism in IFITM3 (SNP RS12252), which is the truncated N-terminal type of IFITM3 in human may be associated with the severe outcomes following infection by IVA (64, 67), human cytomegalovirus (HCMV) (68), and human enterovirus 71 (69), as well as increased incidence and mortality caused by COVID-19 (70–72).