Rotavirus is a ubiquitous
infection that is the leading cause of severe
diarrhea worldwide. Severe
infections are most commonly observed in the first 2 years of life. Rotavirus-induced
diarrhea is associated with substantial morbidity and mortality rates and socioeconomic costs with adverse outcomes particularly prevalent in developing countries. The natural history of
rotavirus infection can provide guidance for the development and optimization of an effective
vaccine. Epidemiologic studies have demonstrated that children who acquire natural
rotavirus infections develop immunity to subsequent
infections, with the protective effect increasing with each natural
infection. Natural
infections also decrease the severity of any subsequent
rotavirus infections. Notably,
asymptomatic infections provide protection similar to that induced by symptomatic
infections. Data also suggest that the antibody response to natural
infection is heterotypic, and therefore may provide protection against multiple serotypes. These data suggest that the development of a
vaccine that produces
asymptomatic infection at an optimal time point may provide effective immunity. An effective
vaccine should mimic protection provided by natural
infection and provide protection against the most common rotavirus serotypes (ie, G1, G2, G3, G4, G9) and be able to decrease disease severity, reduce hospitalizations, and decrease disease-related costs.