Paediatric human metapneumovirus infection: epidemiology, prevention and therapy.

Since its discovery in 2001, human metapneumovirus (hMPV) has been identified as one of the most frequent causes of upper and lower respiratory tract infections. Although a considerable number of hMPV infections are diagnosed in adults and the elderly, the highest incidence of infection is among children as seropositivity for hMPV approaches 100% by 5-10 years of age. Most of the diseases due to hMPV are mild or moderate, tend to resolve spontaneously, and only require outpatient treatment. However, some may be severe enough to require hospitalisation or, albeit rarely, admission to a paediatric intensive care unit because of acute respiratory failure. Mortality is exceptional, but may occur. The most severe diseases generally affect younger patients, prematurely born children, and children who acquire nosocomial hMPV infection and those with a severe chronic underlying disease. Global hMPV infection has a major impact on national health systems, which is why various attempts have recently been made to introduce effective preventive and therapeutic measures; however, although some are already in the phase of development (including vaccines and monoclonal antibodies), there is currently no substantial possibility of prevention and, despite its limitations, ribavirin is still the only possible treatment. Given the risk of severe disease in various groups of high-risk children and the frequency of infection in the otherwise healthy paediatric population, there is an urgent need for further research aimed at developing effective preventive and therapeutic measures against hMPV.