CD8A and infection: Analyzing the frequencies of subjects responsive to different virus peptides combinations (see Figure 2 for flow cytometry strategy), i.e., subjects responsive to at least S, M, or N peptides (including double and triple responders), at least double responders (including triple responders), and exclusively triple responders, we found that at inclusion, convalescent individuals showed similar frequencies of CD8 cell responses to M (63%) and N (47%) proteins compared to infection-naïve individuals with cross-reactive responses (60 and 56%, respectively).