Transient MAIT cell recovery in convalescent COVID-19 patients. (A) Relative frequencies of MAIT cells (left), absolute counts of MAIT cells (middle), and absolute counts of T cells (right) in patients with COVID-19 during the acute (n = 13) and convalescent phase (n = 16 and n = 13 for 4-mo and 9-mo time points, respectively) compared with HDs (n = 11). Mixed-effect analysis and Kruskal–Wallis tests were used to compare paired and nonpaired data. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. (B) Spearman correlation between the absolute count of MAIT cells at the acute phase of COVID-19 infection and the fold change recovery of MAIT cell count between the acute and 4-mo convalescent phase (n = 13). The orange color for moderate and black for severe reflect the disease severity defined at the acute stage (10). The Spearman correlation coefficient (rho) and the associated calculated p value are indicated on the graph.