Epidemiology of acute diarrhea caused by rotavirus in sentinel surveillance sites of Vietnam, 2012-2015.

A prospective, multicentre study was conducted in four sentinel surveillance hospitals to assess the trend and epidemiology of acute diarrhea caused by Rotavirus in Vietnam. During the period 2012-2015, a total 8,889 children under 5 years of age were enrolled in the surveillance, and 8689 stool samples were collected. Of these cases, Rotavirus was most common pathogen 46.7% (4054 cases); in which 26.6% (1117) rotavirus-positive stool samples were evaluated to identify genotypes. The proportion of rotavirus positive specimens decreased annually from 54.7% in 2012 to 36.6% in 2015. Rotavirus was detected year-round, but most rotavirus gastroenteritis cases (77.1%) occurred between December and May, corresponding to the rotavirus seasonality. It is found that the peaks varied by regions. Rotavirus positivities varied between the youngest and oldest age, but children 6-11 months old (38.8%) and 12-23 months old (38.4%) counted for most cases. A significant higher number of diarrhea within 24 hours (8.3 times, 95%CI: 8.1-8.4 times) and higher proportion of severe dehydration (12.9%) in Rotavirus positive group than that in Rotavirus negative group (7.7 times, 95%CI: 7.6-7.9 times; and 9.7%, respectively). A downtrend of prevalence of G1P[8] was observed from 82% in 2013 to 15% in 2015. However, G2P[4] was found in 5% of samples in 2012, 9% in 2013, 36% in 2014, and 28% in 2015. Rotavirus infection is the most important cause of acute diarrhea among hospitalized children in Vietnam, and a rotavirus vaccination program for children may significantly reduce this disease.