The single antibody shot helps stop infants getting chest infections, such as pneumonia, for about six months.A large study has now begun to find out whether nirsevimab should be offered to all babies in the UK. Respiratory syncytial virus (RSV) is the main reason children under five end up in hospital.

Other treatments for RSV already exist and trials of a vaccine have also shown promise.

In a normal winter, RSV mostly causes coughs and colds which clear up in a couple of weeks - but it can be particularly serious in infants under the age of two, causing severe lung problems such as bronchiolitis and pneumonia. Read more HERE.