No evidence of an increase in the incidence of norovirus gastroenteritis hospitalizations in young children after the introduction of universal rotavirus immunization in Israel

Abstract

Following the introduction of universal immunization against rotavirus, concerns were raised regarding pathogen-replacement of rotavirus by norovirus. The study aim was to examine the incidence and characteristics and norovirus gastroenteritis before and after the introduction of universal rotavirus immunization in Israel. We studied 1179 stool samples collected between November 2007 and December 2014 for a prospective hospital-based surveillance study of children aged 0-59 months hospitalized for gastroenteritis. A real-time RT-PCR assay was used to identify genogroup II (GII) norovirus in extracted fecal RNA samples. Overall, the weighted percentage of norovirus positive patients was 10.9%. Norovirus positivity was similar in the pre-universal rotavirus immunisation years (2008-2010) and the universal years (2011-2014), the respective average annual incidence of norovirus gastroenteritis was 1.6 (95% CI 0.6-2.3) per 1000 and 1.1 (95% CI 0.8-1.4) per 1000 children. Rotavirus was detected in 36.8% and 19.6% of the patients in the pre-vaccine years and the universal vaccine years, with an estimated incidence of 5.5 (95% CI 3.4-7.6) per 1000 and 2.1 (95% CI 1.6-2.7) per 1000 children, respectively. Most patients (59.1%) with norovirus gastroenteritis were infants aged 0-11 months. Norovirus was detected all year round with a significant 3-month peak from September through November. In conclusion, norovirus continues to be a leading cause of acute gastroenteritis associated with hospitalizations in young children. Future norovirus vaccines should target young infants. There was no evidence of pathogen-replacement by norovirus following the introduction of universal rotavirus immunization in Israel.

Epidemiological Trends of Five Common Diarrhea-Associated Enteric Viruses Pre- and Post-Rotavirus Vaccine Introduction in Coastal Kenya

“…Due to the shared ecological niche and the apparent decline of all-cause gastroenteritis-associated hospital admissions, it has been hypothesized that rotavirus vaccination has likely impacted the epidemiology of the other enteric viruses [ 5 ]. However, there are contradicting reports on the specific impact of rotavirus vaccination on the prevalence of the individual enteric viruses—for example, norovirus [ 6 , 7 ]. This has not been adequately examined in African populations where diarrhea burden is highest.…”

Vaccines for enteric diseases

“…We have examined the incidence of norovirus gastroenteritis hospitalization in young children before and after the introduction of universal rotavirus immunization in Israel. 47 While no change in the incidence was found between the two periods, we documented the substantial burden and pointed to possible norovirus vaccine target groups. 47…”

“…47 While no change in the incidence was found between the two periods, we documented the substantial burden and pointed to possible norovirus vaccine target groups. 47…”

Evaluation of a bivalent recombinant vaccine candidate targeting norovirus and rotavirus: Antibodies to rotavirus NSP4 exert antidiarrheal effects without virus neutralization

“…Unlike rotavirus, there is currently no commercial vaccine against norovirus, although several vaccines are currently under clinical development (reviewed by Tan 12 ). This lack of vaccines is mainly attributed to the absence of a conventional culture approach for growing human norovirus 13–15 and the lack of a robust animal model for evaluating vaccine candidates. Thus, a new rotavirus vaccine with improved efficacy is in high demand, and parenteral immunization with bivalent recombinant rotavirus and norovirus vaccines should be adopted based on safety, effectiveness, and practicality considerations 16,17 …”