[Epidemiological characteristics and genotype trends of rotavirus diarrhea in China from 2009 to 2020].

To investigate the epidemiological characteristics and genotype trends of rotavirus infection among the population with diarrhea in China, from 2009 to 2020 and provide evidence for strategic surveillance and prevention. Surveillance data on diarrhea syndrome from 252 sentinel hospitals across 28 provinces (municipalities, autonomous regions) were obtained from the information management system of the Infectious Disease Surveillance Technology Platform of the National Science and Technology Major Project. Descriptive epidemiological methods were employed to analyze the distribution of rotavirus diarrhea cases in different climatic zones, populations, and times from 2009 to 2020, as well as the genotyping characteristics and changing trends of group A rotavirus diarrhea cases. From 2009 to 2020, a total of 114 606 diarrhea cases were tested for rotavirus, and the positive rate was 19.1% (21 872/114 606); group A rotavirus was dominant (98.2%, 21 471/21 872). The positive rate of rotavirus was the highest in 2009 (36.9%, 2 436/6 604) and 2010 (30.6%, 5 130/16 790), fluctuated between 14.0% to 18.0% from 2011 to 2017, raised slightly in 2018 (20.3%, 2 211/10 900), and declined continuously in the following two years (15.5%, 2 262/14 611 and 9.5%, 470/4 963). The positive rate of males (20.2%, 13 660/67 471) was significantly higher than that of females (17.4%, 8 212/47 135). Children under five had the highest positive rate (28.4%, 18 261/64 300), more than four times that of adults. The positive rate peaked from December to February in the mediate temperate zone, warm temperate zone, and subtropical zone, while there were two peaks from November to January and May to June in the frigid zone of the plateau. The dominant genotype of group A rotavirus gradually changed from G3P[8] and G1P[8] to G9P[8] during 2009-2020. The overall rotavirus infection rate in China was on a downward trend. Meanwhile, significant variations of positive rates were observed in seasonal epidemics and different age groups from 2009 to 2020. Rotavirus diarrhea in children was still a prominent concern. Vaccination of rotavirus vaccine should be promoted, and the epidemiological characteristics and genotypes of rotavirus diarrhea should be continuously monitored.