Additionally, viral infections could also induce syncytin-1 expression in different cell types, such as Epstein-Barr virus (EBV) and human immunodeficiency virus (HIV) in astrocytes and monocytes [92, 93], and SARS-CoV-2 in Calu-3 cells and A459-ACE2 lung cancer cells [94]. This evidence concerns the gene ERVW-1 and viral infectious disease.