Diarrheal disease and pneumonia are two of the top four causes of mortality in children under the age of five . In 2010, 64 percent of deaths in this age group were due to infectious causes. A majority of these deaths occur in developing countries. Although vaccines have been proven to prevent pneumonia and diarrheal disease due to rotavirus, these vaccines may not be available to the most vulnerable children in developing countries. Barriers to vaccination in the poorest countries include lack of infrastructure, poor health systems, lack of finances, and lack of transportation. It has been estimated that an additional one billion US dollars will be needed to guarantee that the most vulnerable populations receive vaccinations.