Apart from the clear‐cut expansion of naïve and effector CD4+ T helper cells, significantly more CD3+CD8+CD45RO+CD45RA‐ memory T cells were present in the blood of COVID‐19 convalescent patients as compared to healthy controls (113 ± 79 × 106/L vs 87 ± 54 × 106/L; P = .0263) (Figure 2, Figure S4B), which was also reflected by their significantly higher relative levels among CD3+ T cells (8.58 ± 4.67% vs 6.82 ± 3.88%; P < .0045) (Table S4). Here, CD4 is linked to COVID-19.