Hospitalization rates for human metapneumovirus infection among 0- to 3-year-olds in Gipuzkoa (Basque Country), Spain.

Numerous studies have been published on human metapneumovirus (HMPV) infection, but few have been population based. The main aim of this study was to estimate the incidence rate of hospitalization for community-acquired HMPV infection in infants and children aged <3 years. Between July 2004 and June 2007, 796 episodes (742 patients) of community-acquired acute respiratory infection were hospitalized. HMPV was detected in 90 episodes (11.3%). Fifty-nine episodes occurred in infants aged <1 year. The mean length of hospital stay was 6.2 days (range 2-31 days). Thirteen children required admission to the intensive care unit. Viral co-infections were detected in 46 episodes (51.1%). The incidence rate of hospitalization per 1000 inhabitants was 2.6 (95% CI 2.1-3.2), lower than that for respiratory syncytial virus, but higher than that observed for the influenza and parainfluenza viruses. HMPV is a major respiratory pathogen that leads to a high hospitalization rate.