The epidemiology of norovirus gastroenteritis in China: disease burden and distribution of genotypes

With the improvements of sanitation and nationwide safe water supply the occurrence of bacterial diarrhea declined remarkably, while viruses became the leading causes of acute gastroenteritis (AGE). Of these viruses, noroviruses (NoVs) are responsible for a considerable burden of gastroenteritis, especially in children < 2 years and elderly > 65 years. NoVs circulating in the Chinese population are antigenically highly diverse with the genotype GII.4 being the dominant strain followed by GII.3. Given the widespread contamination in environmental sources, and highly infectious nature of NoVs, vaccination would be the desirable strategy for the control of NoV infections. However, a better understanding of acquired immunity after infection, and a reliable immunological surrogate marker are urgently needed, since two vaccine candidates based on virus-like particles (VLPs) are currently moving into clinical evaluations in China.