Respiratory Syncytial Virus (RSV) causes respiratory infection.
It is the commonest cause of severe respiratory illness such as bronchiolitis (inflammation of the bronchioles) in young children aged under 2 years. It is also the commonest cause of hospital admissions due to acute respiratory illness in young children.
RSV infections may be overlooked in older children and adults. Several studies have shown that RSV causes severe respiratory illness in elderly people and that outbreaks are associated with higher death rates. Peak numbers of RSV infections are reported in December and January every winter, although the size of the peak varies from winter to winter.
The Health Protection Agency monitors levels of RSV activity in the UK (see Epidemiological Data). This information is included in the HPA weekly Influenza Report, which is published throughout the winter period. Information also appears in the CDR Weekly during the RSV season.