Human metapnuemovirus infections in hospitalized children and comparison with other respiratory viruses. 2005-2014 prospective study

García-García, María Luz; Calvo, Cristina; Rey, Cristina; Díaz, Beatriz; Molinero, Maria del Mar; Pozo, Francisco; Casas, Inmaculada

The proportion of coinfections with other respiratory viruses of up to 38% in our hospital, was higher than in three states of the U.S. [17] where they found 21% of multiple infections, but they did not test as many respiratory viruses as we did (only HRSV, influenza, and parainfluenza virus). Nevertheless, in Jordan, Schuster et al [13] found up to 53% of coinfections, and rhinovirus and adenovirus were frequently detected in coinfections, as in our country, but they also encountered a substantial number of coinfections with HRSV, being clearly higher than in Spain. This has also been described in other studies, such as Semple [18] in the United Kingdom, where coinfections between HMPV and HRSV were frequent and severe. However, in California [19] , as in our study, only 1% of patients had coinfections between HMPV and HRSV. Probably, the seasonal circulation of HMPV is different among countries or geographical areas and allows that mixed infections were more or less frequent. Hence, in Jordan, HMPV was detected in winter and spring, and they were partly coincident with the circulation of HRSV. However, in Spain, circulation of both viruses was significantly different making coinfections unlikely. February, March, and April were the peak months of HMPV circulation in our country. Clinical data associated with hospitalization due to HMPV was similar to other large studies. In a prospective, population-based surveillance study in the United States [17] , with more than 600 cases, pneumonia (50%), bronchiolitis (22%) and asthma (14%) were the most common diagnosis. In our series, 47% of children had an infiltrate in X-ray, although most of them were diagnosed with recurrent wheezing based on our diagnostic criteria. Up to 53% of children in the US study, and 65% of our patients needed oxygen during the admission. In Jordanian children [13] , clinical diagnoses were similar to ours, with bronchopneumonia and bronchiolitis being more frequent.