IFNG and COVID-19: In clinical trials of a SARS-CoV-2 mRNA vaccine (BNT162b2; Modern VRC) and an adenovirus vector vaccine (AdV5; ChAdOx), SARS-CoV-2-specific CD8+ T cells could secrete high levels of IFN-γ, which was similar to the level of the specific CD8+ T cell response in patients with COVID-19.