To clarify the signal transduction pathway of the gene at the chromosome site where HERV-K (HML-2) gag, env, and pol were highly expressed in COVID-19 patients, we mapped the KEGG database and found that the identified differentially expressed genes (DEGs) were significantly enriched in 30 KEGG pathways (p value ≤ 0.05, Supplementary Table S3). This evidence concerns the gene ERVW-1 and COVID-19.