CD4 and viral infectious disease: Given that polyfunctional T‐cell responses are closely linked to viral control in other viral infections [22, 23], polyfunctional SARS‐CoV‐2‐reactive CD4 T cells were visualized proportionally (Figure 1c) as well as analysed quantitatively (Figure 1d) at 3, 6 and 9 months after recovery from COVID‐19.