Viral airway infection is a very common cause of pneumonia and hospitalisation in children, and it is associated with hyperreactive airways and asthma. The mainstay of therapy remains supportive care, and the prognosis is good. The risk of hospitalisation for flu can be decreased by vaccination of children > 6 months of age. Vaccines against the most common cause of severe lower respiratory tract infection in children, i.e. respiratory syncytial virus, are in development, which is discussed in this review.