Understanding RSV: Severe Disease and the Long Term Consequences

The study design is a case-control, sample based study. 275 cases (Group 1), infants \<12 months old with RSV infection and 40 controls (Group 2), otherwise healthy infants \<12 months old without RSV infection will be recruited. Samples will be taken on enrolment and for infants in Group 1; repeated at 7 weeks convalescence. There will be annual follow up by questionnaire for up to 6 years and a minimum of 1 year, depending at what stage in the study the infant is enrolled.

Human respiratory syncytial virus (RSV) causes severe disease in the very young, elderly and in high risk groups. Worldwide in 2005 there were an estimated 34 million cases of acute lower respiratory tract infection (ALRI), 3.4 million ALRI hospitalisations and 55,000 to 199,000 deaths associated with RSV in children \<5 years old. RSV infection in childhood is associated with subsequent wheezing and asthma. These long-term sequelae pose a substantial additional burden on healthcare systems. There is a parallel need to assemble clinical resources to identify the correlates of severe RSV disease for clinical management, classification of disease severity in clinical trials and identification of biomarkers for severe disease, which are currently lacking. Group 1: Infants under 12 months with an RSV infection will have nasopharyngeal swabs, blood, urine and stool samples taken at the onset of infection and again 6 - 8 weeks later, in convalescence. An online diary will be completed for 2 weeks during illness to record the participant and parent health. The participant and their family will be followed up annually by questionnaire, for a maximum of 6 years. When the study data are analysed, the infants will be subdivided into 4 further groups; healthy infants requiring hospitalisation, healthy infants not requiring hospitalisation, infants with co-morbidity, requiring hospitalisation and infants with a co-morbidity not requiring hospitalisation. Group 2: Well, healthy infants, under 12 months with no acute respiratory infection will have nasopharyngeal swab,blood, urine and stool samples taken on enrolment. They will receive a follow up contact 7 days after enrolment to assess if they have developed any illness. The participant and their family will be followed up annually by questionnaire, for a maximum of 6 years.