Fig. 1

Schematic diagram of principal MR analyses and main flowchart of this study. A, B Schematic diagram for exploring bidirectional causal correlations between various allergic diseases and COVID-19 phenotypes; C exploratory stage for genetically significant correlation between various allergic diseases and COVID-19 phenotypes; D validation stage for genetically significant correlation with other available GWAS datasets (Asthma2018 and ADE2021); E investigating the underlying molecular mechanisms with publicly available GWAS datasets of hematological traits, immune-related cell counts and ACE2 protein expression level in peripheral blood