Elderly patient receiving the 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. The RSV vaccine works by introducing an inactivated RSV protein into the body, which then fuses to host cells and stimulates the immune system to recognise the actual RSV virus, helping to prevent severe disease.