Respiratory syncytial virus infections on both ends of the age spectrum

During my PhD I have looked at disease caused by the respiratory syncytial virus (RSV) in both children and older adults. In children we updated a prediction tool which can identify children at higher risk of severe infection in the first year of life. Next I have looked at the development of asthmatic symptoms such as wheeze in childhood following severe RSV infection in early life. We found that RSV is an independent risk factor for wheezing illness in those without atopic disease but not in those with an atopic constitution. Furthermore, I investigated the agreement between the many surrogates of asthmatic disease that are used interchangeably to define asthma in children. We observed that there is major disagreement between definitions and advise caution in head-to-head comparison. In the second part of my thesis described the incidence and disease burden of RSV in community-dwelling older adults (adults ≥60 years living independently at home). In a large European prospective cohort we observed that RSV is prevalent in community-dwelling older adults but rarely causes severe disease. This suggests that watchful waiting, using a continuity of care approach to identify those who do need more intensive care is often justified when RSV is suspected in family practice. We also observed that exposure to young children may play an important role in the occurrence of respiratory infection in older adults. Last, we observed that worldwide surveillance programs may not detect RSV infection if they use the influenza-like-illness (ILI) case definition because it does not match the clinical symptoms often seen in RSV.