Rotavirus vaccines in developing countries: the potential impact, implementation challenges, and remaining questions.

Diarrhoeal disease is one of the commonest causes of death in children, especially in developing countries in Africa and Asia. Rotavirus has been consistently identified as the commonest pathogen associated with severe diarrhoea. Hence, the availability of vaccines against this organism provides the opportunity to reduce child mortality. Data from efficacy trials in developing countries in Africa and Asia showed that the vaccine efficacy was lower than that observed in other countries. Nevertheless, the vaccines are expected to be of significant benefit in high mortality countries in these regions. While the reports published in this supplement add to our understanding about the performance of these vaccines in developing countries in these regions, questions remain over the overall impact of these vaccines when used in national programmes of developing countries in Africa and Asia, the optimal vaccination schedules and the impact of age restrictions for vaccine use on immunization coverage. Additional research is required to improve understanding on the performance of these vaccines in developing countries in Africa and Asia and measures that may improve performance. Data that will assist in the definition of the optimal immunization schedule and possibly allow relaxation of the age restrictions for vaccine use may help in enhancing the impact of the vaccines in these countries. Finally, disease surveillance and studies are required to document the impact of vaccination and monitor changes in disease epidemiology.