ELF5 and COVID-19: We demonstrate that the strongest and most robust candidate, ELF5 (associated with a >4-fold higher risk to develop severe COVID-19), is specifically expressed in primary target cells of SARS-CoV-2 (for example, sustentacular61, AT246, and secretory or ciliated epithelial cells62) with evidence of co-expression with genes encoding key host factors, such as ACE2 and TMPRSS2, using scnRNAseq data across various sites of the respiratory system.