Epidemiological aspects of rotavirus infection in young Gambian children.

Rotavirus gastro-enteritis in young Gambian children has its maximum impact on infants after the age of one month, in whom it produces short, well-defined annual winter epidemics with clinical dehydration in up to 18% of those infected. Sporadic infection was observed in neonates who were often asymptomatic, throughout one year but not in the subsequent year. In two consecutive years studied there was a major change from subgroup I, serotype 2 to subgroup II, serotypes 1 and 3. This could have contributed to the failure of children to develop protective immunity against sequential disease following an infection during infancy. If rotavirus morbidity in this community is to be notably reduced by a vaccination programme it would need to be carried out in early infancy prior to the winter season. Evaluation of a type-specific vaccine should include monitoring secular changes in rotavirus serotypes throughout subsequent epidemics.