Therefore, three arising hypotheses include: (i) high-level rotavirus-specific maternal immunity (in the form of anti-rotavirus breast-milk IgA and transplacental serum IgG) is a major contributor to failed seroconversion following infant vaccination. (ii) Malnutrition negatively impacts infant immunity and increases the risk of post-vaccination rotavirus gastroenteritis. (iii) Introduction of rotavirus vaccine will alter the molecular epidemiology of circulating rotavirus strains detected in vaccinated children presenting with severe diarrhea.