Seasonality and diversity of group A rotaviruses in Europe

Group A rotaviruses are a major cause of severe gastroenteritis in children under 4 y of age worldwide. Group A rotaviruses have been identified in ma ny animal and bird species, they are antigenically complex, and multiple se rotypes infect humans. Re-assortant rotavirus vaccines are now available wh ich confer protection against severe illness due to rotavirus serotypes G1- 4. Before vaccines are introduced it is necessary to establish the diversit y of rotavirus in the target population to ensure efficacy and to establish a baseline for future surveillance strategies. The purpose of this review is to describe our current knowledge of the diversity of rotaviruses across Europe. Since multinational studies with standardized methodology have not been performed, this review is based on the available published studies. I n Europe, more than 90% of Group A rotavirus strains that have been typed a re of serotypes G1-4, with an average 8% of non-G1-4 strains in published s tudies. The percentage of non-typeable strains may fluctuate from one year to another, and has been as high as 18% in one study in Great Britain, indi cating the need for a more systematic study. Group A rotavirus infection ty pically occurs as a winter peak in the European countries studied. Comparis on of seasonality data from national laboratory surveillance systems showed seasonal differences, with the annual rotavirus peak occurring first in Sp ain, usually in December, followed by France in February, and ending in Nor thern Europe in England and Wales in February or March, and the Netherlands and Finland in March.