Among these DEPs, a number of fundamental proteins, such as ALB, α-2-macroglobulin (A2M) and α-2-HS-glycoprotein (AHSG), were all markedly down-regulated in our dataset and upon new strain infection, indicating that infections of both previous and new SARS-CoV-2 variants can cause strong deteriorative effects with regard to disrupting normal human functions. The gene discussed is A2M; the disease is infection.