CD8A and COVID-19: Although infection offers an opportunity to gain immune protection to diverse SARS-CoV-2 antigen, and some studies have identified strong T-cell responses from individuals with asymptomatic or mild COVID-19, other studies suggest that asymptomatic infection may not provide sufficient antigenic stimulation to activate protective, long-lasting anti-SARS-T-cell response [29, 33], supported by observations that CD8+ T cell responses could not be detected in 30% of convalescent individuals [12].