2020—2022年江苏省新型冠状病毒感染疫情期间流感的流行特征分析

Epidemiological analysis of influenza during COVID-19 epidemic in Jiangsu Province from 2020 to 2022

通过分析2020—2022年江苏省新型冠状病毒感染疫情期间流感的流行特征发现,2020—2022年江苏省共采集90721份流感样病例样本,其中核酸阳性样本6732份,3年平均阳性检出率为7.4%;年度阳性检出率呈现“U”型分布,各年阳性检出率分别为4.4%、3.2%、14.7%,差异具有统计学意义(χ^(2)=12126.00,P<0.001)。2020—2022年流感的季节性高峰时期,病毒在人群中尚未充分流行时出现季节高峰的2次流感活动强度的大幅降低:第一次出现在2020年1—2月,流感核酸阳性检出率从第3周的54.4%(317/583)降至第8周的2.1%(12/584),差异有统计学意义(χ^(2)=394.49,P<0.001);第二次出现在2022年的12月,流感核酸阳性检出率从第49周的14.9%(90/605)降至第52周的1.9%(11/572),差异有统计学意义(χ^(2)=62.88,P<0.001)。2020—2022年江苏省流感疫情具有明显的季节性特征,各月份流感病毒阳性病例分布差异具有统计学意义(χ^(2)=858.00,P<0.001),每年分别有冬、春季(12月至次年3月)和夏、秋季(7—11月)两个流行高峰,流行毒株分别为B-V系和季H3。不同年龄组检测出的流感病例阳性检出率差异有统计学意义(χ^(2)=60.00,P<0.001),5~14岁年龄组流感阳性检出率最高(10.4%),≥60岁年龄组流感阳性检出率相对较低(5.1%),阳性检出率随年龄组升高而降低(趋势检验Z=12.82,P<0.001)。

By analyzing the epidemic characteristics of influenza during the COVID-19 epidemic in Jiangsu Province from 2020 to 2022,it found that 90721 influenza-like case samples were collected in Jiangsu Province from 2020 to 2022,of which 6732 were nucleic acid-positive samples,with an average positive detection rate of 7.4%in three years.The annual positive detection rate presented a U-shaped distribution,with positive detection rates of 4.4%,3.2%and 14.7%,respectively,with statistically significant differences(χ^(2)=12126.00,P<0.001).During the seasonal peak period of influenza from 2020 to 2022,there was a significant decrease in the intensity of the two influenza activity peaks that occurred before the virus became fully prevalent in the population.The first peak occurred from January to February 2020,and the positive detection rate of influenza nucleic acid decreased from 54.4%(317/583)in the third week to 2.1%(12/584)in the eighth week,with a statistically significant difference(χ^(2)=394.49,P<0.001).The second occurred in December 2022,and the positive detection rate of influenza nucleic acid decreased from 14.9%(90/605)at the 49th week to 1.9%(11/572)at the 52nd week,with a statistically significant difference(χ^(2)=62.88,P<0.001).The influenza epidemic in Jiangsu Province from 2020 to 2022 had obvious seasonal characteristics,and the distribution differences of influenza virus-positive cases in each month were statistically significant(χ^(2)=858.00,P<0.001),with two epidemic peaks each year:winter,spring(December to March of the following year),and summer,and autumn(July to November).The epidemic strains were the B-V strain and seasonal H3 strain,respectively.There was a statistically significant difference in the positive detection rate of influenza cases detected in different age groups(χ^(2)=60.00,P<0.001).The age group between 5 and 14 years old had the highest influenza-positive detection rate(10.4%),while the age group≥60 years old had a relatively low influenza-positive detection rate(5.1%).The positive detection rate decreased with the increase in the age group(Ztrend=12.82,P<0.001).