Those SNPs associated with severe RSV disease both at the genotype and allele level included the genes for the vitamin D receptor (VDR), the signal transduction molecule Jun (JUN) which composes part of the AP-1 signaling complex, interferon (IFN)-α (IFNA5) which is a type I IFN involved in early cytokine responses to viral infection, inducible nitric oxide synthase (NOS2A), and the high affinity IgE receptor (FCER1A) important in IgE binding to mast cells, basophils, dendritic cells, and other immune cells. This evidence concerns the gene NOS2 and viral infectious disease.