Additionally, NK cell-specific memory responses have been reported in the context of other viral infections, including HIV-1 and influenza, and following vaccination with Hepatitis B (HBV) antigens79–81,83, and NKG2C+CD57+NK cells from convalescent donors have been shown to produce IFN-γ in response to soluble SARS-CoV-2 peptides53. This evidence concerns the gene KLRC2 and influenza.