| Aim To know the blood serum traits, the distribution and variation trend of influenzaA (H1N1) virus infections and immune responses of different groups of residents inShushan district of Hefei during the epidemic period of the said virus; correctly assessthe validity and scientificity of strategies and measures about its prevention and control;and then, provide effective and scientific strategies and measures and basic data forsimilar epidemic diseases preventing and controlling in the future.Methods Using the method of stratified random sampling, according to Samplingsurvey scheme of influenza A (H1N1) virus infection among population in AnhuiProvince,2304people from street communities and towns in Shushan district wereselected to do the questionnaire investigation. The respondent selection was carried outthree times in2010, which happened in January, March and August, with772,785and747people selected respectively. Through the questionnaire, relevant informationsabout the respondents such as: age, gender, occupation, had or had not suffered frominfluenza like case, immunization history, and so on were collected; meanwhile, theinfluenza A (H1N1) virus-containing blood serum extracted from the blood samples wasisolated, and the virus antibody was detected through the HI test.Results Among the2304respondents, the fluenza A (H1N1) virus antibody positiverate was35.20%(811/2304), in the investigations in January, March and August of2010, the antibody positive rates were39.25%(303/772),36.31%(285/785),29.85%(223/747) respectively, which showed a statistical difference （χ~2=15.33,P=0.009）; the cross sectional analysis indicated that, the difference of influenza A(H1N1) virus antibody positive rates in different epidemic phase and among groupswith different ages, occupations, and some other characteristics such as: live in school or not, live in urban or rural areas, had suffered from influenza like case or not, and soon, had statistical significance. The results of the investigation showed that, in all threetimes, the antibody positive rate of6-15years old group was higher than that of thegroups with other ages, the rate of the students and teachers group was higher than thatof the groups with other occupations. People who live in school were compared withthose who did not live in school, and a statistical difference of the antibody positiverates existed in the first and the second investigations. According to the comparisonbetween people live in urban and rural areas, in the first and the third investigations, theantibody positive rates of the later one were higher than that of the former one; however,in the second investigation, the results of the two groups were basically consistent.Through the vertical analysis of all influencing factors, it could be seen that, for thegroups in which people are6-15or16-24years old; had occupation as student orteacher, lived in school or not; had suffered from influenza like case, common cold orhealthy, the antibody positive rates all presented downward trend. The results of thevertical analysis on people live in urban and rural areas showed that, the difference ofantibody positive rates of people live in urban-rural fringe and urban area had statisticalsignificance（P<0.05）.Among the1823respondents without influenza A (H1N1) vaccine immunizationhistory, the total infection rate was25.45%(464/1823), thereinto, the inapparentinfection rate (infection rate among healthy population) was25.10%(240/956), andthere existed statistical difference among groups with different ages, occupations, livingareas, whether had suffered from influenza like case. From the cross-sectional analysisof the investigations, it could be known that, for all3times, the infection rate ofresidents in Shushan district was about25%; the infection rate of the people who hadsuffered from influenza like case was higher than that of the people who had sufferedfrom common cold or are perfectly healthy. Concerning the age and occupation, theinfection rates of the groups in which people are6-15years old or had occupation asstudent or teacher was relatively higher. According to the comparison between peoplelive in urban and rural areas, in the third investigation, the infection rate of people wholived in urban-rural fringe was high than that of those lived in urban area, however, theresults of the first and the second investigations were basically the same. The vertical comparison showed that, in the3investigations, the infection rates of people who hadsuffered from influenza like case decreased gradually, which were23.08(128/546),19.68%(116/591),13.4%(92/686) respectively; however, the infection rates of thegroups in which people are above60years old and the groups with none of themembers is student or teacher increased, and all reached26%at the third time. Thedifference of the infection rates of other groups classified based on age, occupation,living areas, whether had suffered from influenza like case, and so on, had no statisticalsignificance.According to the study, among the481people with influenza A (H1N1) vaccineimmunization history, the antibody positive rate was72.14%(347/481); however, thecorresponding rate of those people without the immunization history was only25.45%(464/1823), and the difference between them had statistical significance（χ~2=363.71,P<0.001）. In the3investigations, the ratio of people who had influenza A (H1N1)vaccine immunization history were29.27%（226/772）24.71%（194/785）8.17%（61/747）respectively, and the antibody positive rates were75.66%（171/226）,72.68%（141/194）,57.38%（35/61）respectively. Apart from the influence of influenza A (H1N1) vaccineimmunization, the difference of influenza A (H1N1) virus antibody positive ratesbetween populations with and without seasonal influenza vaccine immunization historyhad no statistical significance.Conclusions The influenza A (H1N1) virus antibody positive rate of residents inShushan district of Hefei city in2010presented a downward trend, the infection rateremained almost unchanged. Inoculating the influenza A (H1N1) vaccine is an effectiveway to improve human immunity, and the antibody level of the vaccine inoculators areinfluenced by occupation, age, whether have suffered from influenza like case, andlength of time interval. During the prime and the middle epidemic period of the disease,the influenza A (H1N1) virus antibody positive rates and the infection rates of people indifferent groups classified based on age, occupation, living areas, whether had sufferedfrom influenza like case, and whether had close contacted with other patients, are alldifferent; whereas, during the late epidemic period, the difference of infection ratesamong different population groups had no statistical significance, and the amount ofpatients suffered from influenza like case decreased obviously. |
PDF Full Text Request