目的:了解天津市2019年散发急性胃肠炎患儿中诺如病毒(Norovirus, NoV)感染的分子流行病学特征。方法:收集2019年1—12月就诊于天津市儿童医院住院散发急性胃肠炎患儿的粪便标本3 116份，收集患儿临床资料和个人信息，采用实时荧光定量PCR方法对NoV进行初筛，应用反转录PCR方法对初筛阳性标本的聚合酶区和衣壳蛋白区进行扩增，并对序列进行比对和系统进化分析。结果:3 116份粪便标本中检出NoV阳性809份，阳性率为26.0%(809/3 116)。不同年龄组NoV检出率差异有统计学意义(n P＝0.000)，其中7～12月龄组检出率最高(31.6%)；不同季节间NoV检出率差异有统计学意义，其中冬季为高发季节(39.0%)。序列分析发现，286份阳性标本的两个区域均测序成功，分成6个基因型，分别是GⅡ.P12-GⅡ.3，GⅡ.P16-GⅡ.2，GⅡ.P17-GⅡ.17，GⅡ.Pe-GⅡ.2，GⅡ.Pe-GⅡ.3和GⅡ.Pe-GⅡ.4。其中以GⅡ.Pe-GⅡ.4为主，占61.2%(175/286)。其次为GⅡ.P12-GⅡ.3，占33.6%(96/286)；GⅡ.Pe-GⅡ.3占2.4%(7/286)；GⅡ.P16-GⅡ.2占2.1% (6/286)；GⅡ.Pe-GⅡ.2和GⅡ.P17-GⅡ.17均占0.3% (1/286)。GⅡ.Pe-GⅡ.4中全部为GⅡ.Pe-GⅡ.4 Sydney 2012。携带GⅡ.Pe-GⅡ.4 Sydney 2012型NoV患儿较GⅡ.P12-GⅡ.3更容易出现呕吐。n 结论:NoV是儿童病毒性急性胃肠炎的重要病原体，GⅡ.Pe-GⅡ.4 Sydney 2012和GⅡ.P12-GⅡ.3是2019年天津地区住院散发急性胃肠炎中NoV感染的主要流行株。“,”Objective:To investigate the molecular epidemiological characteristics of norovirus (NoV) in hospitalized children with sporadic acute gastroenteritis in Tianjin in 2019.Methods:Fecal specimens and clinical data were collected from 3 116 hospitalized children with sporadic acute gastroenteritis possibly caused by viral infection in Tianjin Children′ Hospital between January and December, 2019. Real-time quantitative PCR was used to detect NoV. Partial sequences of RNA-dependent RNA polymerase (RdRp) and capsid genes of NoV were amplified by RT-PCR. Sequence alignment and phylogenetic analysis were performed for further analysis.Results:Among the 3 116 specimens, 809 (26.0%) were positive for NoV. There were significant differences in NoV detection rate between different age groups (n P=0.000), and the highest NoV detection rate (31.6%) was observed in the age group of 7-12 months. Moreover, the detection rate of NoV varied with seasons (n P=0.000), and the NoV detection rate was highest in winter (39.0%). Based on the sequence analysis of RdRp and capsid genes, 286 identified NoV strains belonged to six genotypes, which were GⅡ.P12-GⅡ.3, GⅡ.P16-GⅡ.2, GⅡ.P17-GⅡ.17, GⅡ.Pe-GⅡ.2, GⅡ.Pe-GⅡ.3 and GⅡ.Pe-GⅡ.4. The predominant genotype was GⅡ.Pe-GⅡ.4 Sydney 2012 (61.2%), followed by GⅡ.P12-GⅡ.3 (33.6%, 96/286), GⅡ.Pe-GⅡ.3 (2.4%, 7/286), GⅡ.P16-GⅡ.2 (2.1%, 6/286), GⅡ.Pe-GⅡ.2 (0.3%, 1/286) and GⅡ.P17-GⅡ.17 (0.3%, 1/286). Patients carrying the NoV of GⅡ.Pe-GⅡ.4 Sydney 2012 genotype were likely to suffer from vomiting than those positive for NoV of GⅡ.P12-GⅡ.3 genotype.n Conclusions:NoV was an important pathogen causing acute gastroenteritis in children. GⅡ.Pe-GⅡ.4 Sydney 2012 and GⅡ.P12-GⅡ.3 were the major genotypes of NoV in hospitalized children with sporadic acute gastroenteritis in Tianjin in 2019.