Burden of Norovirus and Rotavirus in Children After Rotavirus Vaccine Introduction, Cochabamba, Bolivia.

The effectiveness of rotavirus vaccine in the field may set the stage for a changing landscape of diarrheal illness affecting children worldwide. Norovirus and rotavirus are the two major viral enteropathogens of childhood. This study describes the prevalence of norovirus and rotavirus 2 years after widespread rotavirus vaccination in Cochabamba, Bolivia. Stool samples from hospitalized children with acute gastroenteritis (AGE) and outpatients aged 5-24 months without AGE were recruited from an urban hospital serving Bolivia's third largest city. Both viruses were genotyped, and norovirus GII.4 was further sequenced. Norovirus was found much more frequently than rotavirus. Norovirus was detected in 69/201 (34.3%) of specimens from children with AGE and 13/71 (18.3%) of those without diarrhea. Rotavirus was detected in 38/201 (18.9%) of diarrheal specimens and 3/71 (4.2%) of non-diarrheal specimens. Norovirus GII was identified in 97.8% of norovirus-positive samples; GII.4 was the most common genotype (71.4% of typed specimens). Rotavirus G3P[8] was the most prevalent rotavirus genotype (44.0% of typed specimens) and G2P[4] was second most prevalent (16.0% of typed specimens). This community is likely part of a trend toward norovirus predominance over rotavirus in children after widespread vaccination against rotavirus.