Global networks for surveillance of rotavirus gastroenteritis, 2001-200.

Rotavirus infection is the leading cause of severe acute diarrhoea among young children worldwide.1, 2 An estimated 527 000 children aged <5 years die from rotavirus diarrhoea every year, with >85% of these deaths occurring in low-income countries in Africa and Asia.3 Two recently licensed rotavirus vaccines have shown effi cacy of 85–98% against severe rotavirus diarrhoea in trials conducted in WHO’s Region of the Americas and the European Region4, 5 and, since 2006, they have been introduced into the routine immunization programme in 11 countries in these regions. Trials of these vaccines continue in order to assess effi cacy in low-income countries in Asia and Africa where differences in several factors (for example, a greater prevalence of concurrent enteric infections, a greater prevalence of malnutrition, a greater prevalence of unusual rotavirus strains) could potentially affect vaccine performance. Results of these trials are expected within 1–2 years and, if they demonstrate that the vaccine is effi cacious, rotavirus vaccines might soon be recommended for global use by WHO. In order for policy-makers to make well informed decisions about introducing rotavirus vaccines into their immunization programmes, data on the epidemiology and burden of severe rotavirus disease are vital. Therefore, WHO, in collaboration with its partners, has established networks of hospital-based sentinel surveillance sites to detect rotavirus diar-