Epidemiological profile and burden of rotavirus diarrhea in Vietnam: 5 years of sentinel hospital surveillance, 1998-2003.

For 5 years, we have conducted sentinel surveillance for rotavirus at 6 hospitals in 4 cities in Vietnam. Stool samples obtained from >10,000 children <5 years old who were admitted to the hospital with diarrhea have been screened for rotavirus. Overall, 55% of samples were positive, and there was little variability in rates of detection of rotavirus between sites (44%-62%). In Vietnam, the characteristics of rotavirus infection more closely resemble those seen in developed countries, rather than those seen in developing countries: children become infected at an older age, the percentage of stool samples in which rotavirus is detected is extremely high, and the rotavirus strains appear to be the common types, with fewer mixed infections occurring. It is estimated that 5300-6800 children <5 years old die of rotavirus infection each year in Vietnam, representing 8%-11% of all deaths in this age group (cumulative risk per child by age 5 years, 1 in 200 to 1 in 285). Additional studies are ongoing to document the economic cost of the disease and to assess the burden of both fatal cases and milder cases of disease. Study outcomes will provide information for future testing and potential use of a rotavirus vaccine.