Burden of acute gastroenteritis caused by norovirus in China: A systematic review. Issue 3 (September 2017) - Zhou, Hong-Lu
Summary: Background: To understand the epidemiology and disease burden of norovirus (NoVs) gastroenteritis in China, a systematic review was conducted. Methods: Studies on acute gastroenteritis (AGE) caused by NoVs from mainland China, published before 2017 were searched. All retrieved articles were screened and reviewed by a standardized algorithm. NoVs detection rates as well as strain variations by ages, seasonal variations and geographic locations were analyzed using random-effects model. Results: A total of 225 articles were included in the final analysis. Similar detection rates at 21.0% and 19.8% were obtained from the North and the South, respectively. NoVs infection occurred year round, with a peak between October and January in the North and between August and November in the South. High detection rates (∼29%) of NoVs were found in adults and the elderly and in children aged 6–35 months (∼22%). The predominant strains were GII.4 (70.4%), followed by GII.3 (13.5%). Conclusion: NoVs cause significant disease burden in China which warrants development of vaccines against NoVs, particularly for children and the elderly who are vulnerable to gastroenteritis diseases. To achieve a broad protection, continual monitoring NoV epidemics and strain variations for selection of proper vaccine strains is critical. Highlights: This is the first report on disease burden caused by norovirus in China. Three vaccine candidates are being developed in China, while critical epidemiological information is absent. The "U" shape with lowest rate in children aged 5-17 years seems can't infer that natural immunity does not exceed 2-year. A remarkable incidence of 15.6/100 children/year was estimated among children less than 5 years of age.