We then evaluated the expression of four interferon-stimulated genes (ISGs) acting on different steps of viral infection (i.e., OAS1, IFITM3, ISG15, and MxA) in lysates of nasal HAEs infected with each single virus or coinfected with the two viruses simultaneously or sequentially 1 or 4 days apart (Fig. 2). The gene discussed is IFITM3; the disease is viral infectious disease.