探讨2017—2022年，成都市儿童流行性感冒(简称为流感)流行特征及儿童早期预警评分(PEWS)对患儿病情严重程度的预测。

选择2017年1月至2022年9月，于成都市第二人民医院、四川大学华西第二医院、成都市青白江区人民医院及成都市锦江区莲新社区卫生服务中心4家医疗机构确诊的6 785例流感患儿为研究对象。采取回顾性分析法，按照病情轻重将其分别纳入轻症组(n＝6 141，普通患儿)，重症组(n＝448，重症患儿)及危重症组(n＝196，危重患儿)。采用χ²检验，对甲型与乙型流感患儿的重症+危重症发生率进行统计学比较；采用方差分析及Bonferroni法，对3组患儿PEWS进行总体及两两比较；通过受试者工作特征(ROC)曲线，分析PEWS预测患儿发生流感重症及危重症的最佳临界值。本研究遵循的程序经成都市第二人民医院伦理委员会批准(审批文号：202212)。所有患儿监护人知情同意。

①防治新型冠状病毒感染(COVID-19)疫情的非药物干预(NPIs)措施实施前(2017年1月至2019年12月)，儿童冬、春季感染甲型流感病毒为主，多发生于婴儿期、幼儿期及学龄前期儿童，共计占比为75.7%(4 280/5 654)，重症+危重症患儿占比为10.1%；NPIs实施后(2020年1月至2022年9月)，儿童以感染乙型流感病毒为主，甲型、乙型流感病毒交替感染小流行，以学龄期+青春期儿童感染为主，共计占比为66.1%(748/1 131)，重症+危重症患儿占比为6.3%。②本研究轻症组、重症组及危重症组患儿PEWS分别为(0.27±0.57)分、(2.44±0.64)分及(5.16±1.17)分，重症组及危重症组患儿PEWS分别高于轻症组，并且差异均有统计学意义(t＝5.46、35.92，P<0.001、0.001)。③甲型流感患儿的重症+危重症发生率为9.9%(472/4 757)，高于乙型流感患儿的8.5%(172/2 028)，并且差异有统计学意义(χ²＝19.88，P<0.001)。重症+危重症患儿中，甲型流感患儿的PEWS高于乙型流感患儿[(4.33±0.55)分vs (3.58±0.25)分，t＝4.74、P<0.001]；④PEWS预测流感患儿发生重症的ROC曲线下面积(AUC)为0.916±0.041，最佳临界值为2.50分；PEWS预测流感重症患儿发生危重症的ROC-AUC为0.959±0.017，最佳临界值为5.21分。

NPIs实施后，成都市儿童流感呈现低水平流行，甲、乙型流感病毒感染交替流行。PEWS可预测儿童流感病情严重程度。

To explore the epidemiological characteristics of pediatric influenza in Chengdu from 2017 to 2022 and the application of pediatric early warning score (PEWS) in prediction of the severity of illness in children.

From January 2017 to September 2022, a total of 6 785 pediatric influenza cases were selected from 4 medical institutions, including Chengdu Second People′s Hospital, West China Second University Hospital, Sichuan University, Chengdu Qingbaijiang District People′s Hospital, and Lianxin Community Health Center, Jinjiang District, Chengdu. Took retrospective analysis method, according to the severity of illness, they were divided into three groups: mild group (n=6 141, ordinary cases), severe group (n=448, severe cases) and critical group (n=196, critical cases). The clinical data of children were analyzed retrospectively. Chi-square test was used to compare the incidence rate of severe and critical cases between influenza A and influenza B children. One-way ANOVA and Bonferroni method were used to overall and pairwise compare the PEWS among the three groups. The receiver operating characteristic (ROC) curve was used to analyze the optimal threshold score of PEWS in predicting the occurrence of severe and critical influenza in children. All procedures in this study were approved by the Ethics Committee of Chengdu Second People′s Hospital (Approval No. 202212). Informed consents were obtained from guardians of all children.

① Before the implementation of non-pharmaceutical interventions (NPIs) for preventing and control the coronavirus disease 2019 (COVID-19) (from Janurary 2017 to September 2019), children were mainly infected with influenza A virus in winter and spring. It mainly affected infants, toddlers, and preschoolers, the total proportion was 75.7% (4 280/5 654), the proportion of severe and critical cases was 10.1%. After implementation of NPIs (from January 2020 to September 2022), children were mainly infected with influenza B virus, and influenza A and B viruses were alternately infected with small epidemics. School-age and adolescents were primarily affected, with the total proportion of 66.1% (748/1 131), the proportion of severe and critical cases was 6.3%. ②The PEWS of children in mild group, severe group and critical group were (0.27±0.57) score, (2.44±0.64) score and (5.16±1.17) score, respectively, the PEWS of children in severe and critical group were higher than those of in mild group, respectively, and the differences were statistically significant (t=5.46, 35.92; both with P<0.001). ③The incidence rate of severe and critical cases in influenza A children was 9.9% (472/4 757), which was higher than that in influenza B children (8.5%, 172/2 028), and the difference was statistically significant (χ²=19.88, P<0.001). Among severe and critical cases, the PEWS of influenza A children was (4.33±0.55) score, which was higher than that of (3.58±0.25) score in influenza B children, and the difference was statistically significant (t=4.74, P<0.001). ④The area under the ROC curve (ROC-AUC) of PEWS predicting severe influenza in influenza children was 0.916±0.041, and the optimal threshold score was PEWS with 2.50 score; The ROC-AUC of PEWS predicting critical influenza in severe influenza children was 0.959±0.017, the optimal threshold score was PEWS with 5.21 score.

After the implementation of NPIs, the pediatric influenza in Chengdu showed a low level epidemic, with alternating of influenza A and B virus infection. The PEWS can be used to predict the severity of influenza in children.