[Rotavirus infections and their prevention with vaccines in children].

Human rotaviruses are the most common cause of severe diarrhoea in children under two years in developing countries: the need of an effective rotavirus vaccine, safe, easy to administer and compatible with existing immunization schedules is now well-established. Molecular structure of rotaviruses (fragmented genome) and their antigenic variability (four human serotypes without cross-reactivity) explain some difficulties in vaccinal strategy. Furthermore, specific efficacy is not clearly evaluable because many others pathogens are responsible of diarrhoea. Immunological response is influenced by serological status before immunization, antigenicity of vaccinal strains, age of immunization. For all these reasons, some contradictory results are emerging from published field trials. Present candidate rotavirus vaccines are live vaccines, with oral administration of bovine or simian rotaviruses; recombinant and polyvalent strains were constructed and were under evaluation; a better strategy for dose administration, target population and interference with other live vaccines is in progress.