We analysed surface IL-18Rα expression on CD8 T cells, CD4 T cells and monocytes in the blood from 43 hospitalized RSV, COVID-19, influenza A and influenza B patients during their hospital stays, in comparison to IL-18Rα levels detected in healthy individuals (Supplementary Table 1,2, Supplementary Fig. 2a). Here, CD8A is linked to COVID-19.