CD8A and infection: In inactivated vaccine-healthy individuals, the memory T cell responses to BA.1 and BA.4/5, including CD4+ helper subsets (Figure 5A), CD4+ memory subsets (Figure 5B), CD8+ memory subsets (Figure 5C), the polyfunctional profiles of CD4+ T cell (Figure 5D) and CD8+ T cell (Figure 5E), were similar with the pattern in breakthrough infection individuals.