The PBMC collected from Tibetan individuals, exposed to prior SARS-CoV-2 infection or received the related COVID-19 vaccines, when incubated with SARS-CoV-2 RBD peptide, had elevated expression of IFNγ in PHD2D4E;C127S memory T cells under hypoxia, indicating a protective effect of these variants against COVID-19 infections in native Tibetan highlanders living under a hypobaric hypoxic environment. The gene discussed is IFNG; the disease is COVID-19.