2357例流感样患儿甲乙型流感病毒检测结果及病毒载量分析

Detection of influenza A and B viruses and viral loads in 2 357 children with influenza-like illness

目的分析流感流行季节杭州地区儿童甲乙型流感的流行特征及病毒载量值(copies/ml),为儿童流感诊断治疗提供指导。方法纳入2017年12月-2018年3月就诊于杭州市儿童医院符合流感样病例的患者共2 357例,采集血液进行实验室常规指标检测,同时采用实时荧光定量聚合酶链式反应进行鼻咽拭子标本核酸检测,确诊甲乙型流感病毒类型及其病毒载量。分析高病毒载量与低病毒载量患儿实验室常规指标差异。比较上呼吸道感染与合并下呼吸道感染患儿病毒载量差异。结果共检测到1 026例甲乙型流感阳性病例,阳性率43.36%。其中甲型流感663例(64.62%),乙型流感363例(35.38%),两组中位年龄具有显著性差异(P<0.001)。0~5月龄患儿甲型流感病毒载量最高为(5.25±1.74)log10(copies/ml),随年龄增长病毒载量逐渐下降,不同年龄段病毒载量差异有统计学意义(t=3.748,P=0.011)。乙型流感阳性患儿不同年龄段病毒载量未见统计学差异(t=0.468,P=0.705)。甲流感染患儿高病毒载量组淋巴细胞比例为(28.99±15.23)%低于低病毒载量组的(32.03±18.37)%,比较差异有统计学意义(t=2.318,P=0.021);乙流感染患者高病毒载量组与低病毒载量组之间各常规指标均未见统计学差异。合并下呼吸道感染患儿病毒载量均显著高于上呼吸道感染患儿(P<0.001)。结论本地区本次流感流行期间甲型和乙型流感病毒具有不同的流行病学特征,合并下呼吸道感染患儿具有较高的病毒载量,病毒载量可作为评估流感患儿病情轻重程度的参考指标。

OBJECTIVE To investigate the epidemiological characteristics of influenza A and B in the children of Hangzhou during the season of influenza pandemic and analyze the value of viral loads(copies/ml) so as to provide guidance for diagnosis and treatment of the children with influenza. METHODS A total of 2 357 children with influenza-like illness who were treated in Hangzhou Children′ Hospital from Dec 2017 to Mar 2018 were enrolled in the study, the blood specimens were collected for laboratory routine indexes test, the nucleic acid test for nasopharyngeal swab specimens was carried out by using real-time fluorescence quantitative polymerase chain reaction(PCR) so as to determine the type of influenza virus and the viral load.The routine laboratory indexes were compared between the high viral load children and the low viral load children, and the viral load was compared between the children with upper respiratory tract infection and the children with lower respiratory tract infection. RESULTS Totally 1 026 children were tested positive for influenza A and B, with the positive rate 43.36%, of whom 663(64.62%) had influenza A, and 363(35.38%) had influenza B, and there was significant difference in the median age between the two groups(P<0.001).The viral load of the influenza A children aged between 0 and 5 months was the highest(5.25±1.74)log10(copies/ml), the viral load was decreased with the age, and there was significant difference in the viral load among the different age groups of children(t=3.748,P=0.011).There was no significant difference in the viral load among the different age groups of influenza B-positive children(t=0.468,P=0.705).Among the children with influenza A, the percentage of lymphocytes of the high viral load group was(28.99±15.23)%, significantly lower than(32.03±18.37)% of the low viral load group(t=2.318,P=0.021). Among the patients with influenza B, there were no significant differences in the routine indexes between the high viral load group and the low viral load group.The viral loads of the children complicated with lower respiratory tract infection were significantly higher than those of the children complicated with upper respiratory tract infection(P<0.001). CONCLUSION The influenza A and B viruses vary in the epidemiological characteristics in this area during the influenza epidemic, the viral loads of the children complicated with lower respiratory tract infection are relatively high, and the viral load can serve as a reference index for prediction of severity of illness.