Objectives: Previous studies indicate a high burden of diarrhoeal disease in Vietnamese children,
however longitudinal community-based data on burden and aetiology are limited. The findings from a
large, prospective cohort study of diarrhoeal disease in infants in southern Vietnam are presented herein.
Methods: Infants were enrolled at birth in urban Ho Chi Minh City and a semi-rural district in southern
Vietnam, and followed for 12 months (n = 6706). Diarrhoeal illness episodes were identified through
clinic-based passive surveillance, hospital admissions, and self-reports.
Results: The minimum incidence of diarrhoeal illness in the first year of life was 271/1000 infant-years of
observation for the whole cohort. Rotavirus was the most commonly detected pathogen (50 of positive
samples), followed by norovirus (24 ), Campylobacter (20 ), Salmonella (18 ), and Shigella (16 ).
Repeat infections were identified in 9 of infants infected with rotavirus, norovirus, Shigella, or Campylobacter, and 13 of those with Salmonella infections.
Conclusions: The minimum incidence of diarrhoeal disease in infants in both urban and semi-rural
settings in southern Vietnam was quantified prospectively. A large proportion of laboratory-diagnosed disease was caused by rotavirus and norovirus. These data highlight the unmet need for a rotavirus vaccine in Vietnam and provide evidence of the previously unrecognized burden of norovirus in infants.