Respiratory syncytial virus (RSV) is an enveloped RNA virus and is in the same family as the human parainfluenza viruses and mumps and measles viruses. RSV is one of the common viruses that cause coughs and colds in winter.
RSV usually causes mild respiratory infection in adults and children, but it can be severe in infants who are at increased risk of acute lower respiratory tract infection. RSV is the most common cause of bronchiolitis in children aged under 2 years.
Public Health England monitors levels of RSV activity in England and Wales and publishes information throughout the RSV season.