Focusing on pneumonia, which is the target of this review, and omitting better-known RSV bronchiolitis, subjects affected by RSV pneumonia usually present with the following features: fever, signs and symptoms of acute respiratory infections (cough, wheezing, tachypnoea), hypoxaemia and oxygen necessity, alteration of reactive C protein (CRP), and radiographic evidence (increased pulmonary texture or mottled shadows) [48,50,55,76,77]. This evidence concerns the gene CRP and pneumonia.