These 18 essential genes include IRF7, IFIH1, IFITM2, etc., and GO and KEGG analysis indicate that these DEGs are enriched in the viral process, response to the virus, the regulation of response to cytokine stimulus, and leukocyte homeostasis, which again highlights the important roles of immune responses in both AD progression and SARS-CoV-2 infection (Figure 6B and Figure S1E). This evidence concerns the gene IFIH1 and Alzheimer disease.