Epidemiology of respiratory syncytial virus infection among paediatric patients in Hong Kong: seasonality and disease impact.

In a 5-year retrospective survey of respiratory syncytial virus (RSV) infections among hospitalized children, 1340 cases were identified of which, 98.4% were children < 5 years old with a male:female ratio of 1.5: 1. Most cases occurred from April to September showing a significant positive correlation with temperature and relative humidity. Community-acquired infections accounted for 92.5% of the cases with a mean hospital stay of 5 days. The estimated annual incidence of RSV infection requiring hospitalization was 2.5/1000 children < 5 years old with a mortality of 0.15% among hospitalized cases. On average, 248 children were admitted each year to the 1400-bed acute regional hospital accounting for an expenditure of HK S1.94 ((approximately US +/-0.25) million for hospitalization costs which equates to an annual cost in excess of HK $6.67 (approximately US $0.86) million for the whole of Hong Kong. An RSV vaccine should be a priority.