Concerns have been expressed about the pathogen-replacement of rotavirus by norovirus after the introduction of universal rotavirus vaccination. The purpose of the study was to compare the prevalence and features of norovirus gastroenteritis in Israel before and after the introduction of universal rotavirus vaccination. Researchers examined 1179 stool samples obtained between November 2007 and December 2014 for a prospective hospital-based surveillance study of children aged 0–59 months admitted to the hospital with gastroenteritis. The genogroup II (GII) norovirus was identified in extracted fecal RNA samples using a real-time RT-PCR technique. The weighted percentage of norovirus-positive patients was 10.9 percent overall. The average yearly incidence of norovirus gastroenteritis was 1.6 per 1000 children in the pre-universal rotavirus immunization years and 1.1 per 1000 children in the universal years. Rotavirus was found in 36.8 percent of patients in the pre-vaccination years and 19.6 percent of patients in the universal vaccine years, with an estimated frequency of 5.5 per 1000 and 2.1 per 1000 children, respectively. The majority of norovirus gastroenteritis patients were babies aged 0–11 months. Norovirus was found all year, with a major three-month surge from September to November.
To summarise, norovirus is a significant cause of acute gastroenteritis linked with hospitalizations in young children. Future norovirus vaccines should be aimed at newborns. Following the implementation of the universal rotavirus vaccine in Israel, there was no indication of pathogen substitution by norovirus.