Fig. 3

Scatter plots showing significant causal effects of peripheral blood hematological traits and immune-related cells on COVID-19 infection/severity. A, B Significant causal effects of monocytes on COVID-19 A2 and B2; C–E significant causal effects of the ratio of CD4⁺ T/CD8⁺ T cells on COVID-19 A2, B2, and C2; F, G significant causal effects of CD8⁺ T cells on COVID-19 A2 and B2; H significant causal effects of COVID-19 A2 on mean cell hemoglobin. Scatter plots for CD4⁺ T and CD56⁺ natural killer cells could not be drawn as only one valid SNP in MR analysis