CD8A and COVID-19: SARS-CoV-2 S-, M-, and N-specific CD8+ T cell responses (CD69+CD137+) were detected in 14, 19, and 6 individuals recovered from COVID-19 with symptoms, and the magnitudes of the SARS-CoV-2-specific CD8+ T cell responses measured were 0.17 (IQR: 0.08–0.40), 0.40 (IQR: 0.19–0.62) and 0.04 (IQR: 0.01–0.11), respectively (Fig. 4a, b).