Respiratory syncytial virus (RSV) vaccine. RSV is a common respiratory virus that can lead to severe lung infections such as pneumonia and bronchiolitis, which can make babies and older adults seriously ill. The RSV vaccine was approved for use in the UK for the first time in September 2024. In preparation for winter, the NHS (National Health Service) will vaccinate pregnant women and those aged 75 and older. Research on thousands of women around the world who have been vaccinated against RSV shows that it reduces the risk of severe lung infection in infants by around 70 percent in the first six months of life.