2010年长沙市甲型H1N1流感大流行血清学流行病学调查

目的掌握2010年长沙市甲流流行期间不同时点及人群甲型H1N1型流感血清流行病学特征。方法 2010年1月、3月、8月使用多阶段随机抽样方法在全市5个区,按照0~、6~、16~、25~和60~岁5个年龄组随机抽取一定数量的研究对象开展三次横断面调查,每次均对调查对象进行问卷调查,并采集静脉血进行甲型H1N1流感血凝抑制试验。结果 5个年龄组人群中,6~岁组和16~岁组甲流血清抗体阳性率都随着时间的推移呈现下降趋势,以6~岁组的下降幅度较大,其抗体滴度几何均数(GMT)下降幅度也较大。6个职业组人群中,学生和医务人员组甲流血清抗体阳性率都随着时间的推移呈现下降趋势,学生组下降幅度较大。不同性别间血清抗体阳性率和GMT差异均无统计学意义(P0.05)。综合三次调查结果,接种甲流疫苗后,人群的甲流血清抗体阳性率达到55.53%,为未接种流感疫苗人群的2.15倍;抗体GMT达到44.62,为未接种甲流疫苗人群的3.74倍。结论 2010年长沙市甲流流行趋势趋于缓和,初步形成免疫屏障;学生和医务人员是感染甲流的高风险人群;接种甲流疫苗后人群有较高的抗体阳性率,但是抗体水平下降较快;接种甲流疫苗对人群有一定的保护作用,应加强对60岁及以上人群甲流疫苗的接种和补种。

A sero-epidemiological investigation on 2010 H1N1 influenza A epidemic in Changsha City

Objective To investigate the sero-epidemiological characteristics of different age groups at different time points during the 2010 H1N1 influenza A epidemic in Changsha City.Methods Three cross-sectional surveys were conducted in 5 districts of Changsha City in January,March and August 2010.The respondents were selected by multiple random sampling and were divided into 5 age groups （0-,6-,16-,25-and 60-years） for face-to-face questionnaires,and their serum specimens were collected and tested for antibody against the influenza A （H1N1） 2010 virus by hemagglutination inhibition （HI）.Results Among 5 different age groups,the positive rates of the antibody against the influenza A （H1N1） 2010 virus in the age groups of 6-and 16-years showed a downward trend over time; moreover,the positive rate and the geometric mean antibody titer （GMT） of the antibody both declined more greatly in the age group of 6-years.Among 6 different occupation groups,the positive rates of antibody against the influenza A （H1N1） 2010 virus in the student and medical professional groups showed a downward trend over time,with more decrease in the student group.No statistically significant difference was found in the positive rate and GMT between genders （P＞0.05）.The comprehensive analysis of the 3 surveys showed that the positive rate and GMT of the antibody against the influenza A （H1N1） 2010 virus in the vaccinated population reached 55.53％ and 44.62 respectively,which were 2.15 and 3.74 times of those in the unvaccinated population.Conclusions The epidemic of influenza A （H1N1） in Changsha City appeared to be subsiding over time in 2010,and the immunological barrier formed preliminarily.Students and medical professionals are at high-risk for influenza A （H1N1） virus infection.The vaccinated population shows a high positive rate of antibody against influenza A （H1 N1） virus; however,their antibody levels decrease rapidly.H1 N1 vaccine has a protective effect on the crowd.It is necessary to intensi