An international collaborative study on influenza viruses antibody titers and contact patterns of individuals in rural and urban household of Guangzhou

Abstract

To describe the influenza viruses antibody levels and contact patterns of individuals in rural and urban regions of Guangzhou and to understand how contact patterns and other factors would correlate with the levels on the titers of antibody.

OBJECTIVE To describe the influenza viruses antibody levels and contact patterns of individuals in rural and urban regions of Guangzhou and to understand how contact patterns and other factors would correlate with the levels on the titers of antibody. METHODS “Google Map” was used to randomly select the study points from the administrative areas in Guangzhou region. Each participant was required to provide 5 ml blood serum sample to be tested against different strains of H1N1 and H3N2 influenza viruses. RESULTS 1) Using“Google map”, 50 study points were selected but only 40 study points would meet the inclusion criteria. The cohort of this study consisted 856 households with 2801 individuals. 1821 participants (65% of the total number individuals in the cohort) completed the questionnaires. Among the l821 participants, 77.3% (1407/1821) and 22.7% (414/1821) of them were from rural and urban areas respectively. There were more male participants in the rural but more female participants in the urban regions. Majority of the participants were from age group 18-59 followed by group 60 with aged 2-17 the least, in both rural and urban areas. 2) 78.1% (1423/1821) of the participants provided their serum samples. There appeared a strong correlation between age of the particitIants and the strength of their antibodies against that strain when a strain first circulated. In particular, seroprevalence was the highest at the age group 2-17. 3) ‘Contact’was defined as persons having physical touch or/and conversation within one meter with the participants. Participants reported all having had large number of contacts. The proportion of participants having contacts with ten persons or above was the highest, ranging from 49.8% to 72.6%, particularly in age group 6-17. Compared to weekdays, participants had fewer contact persons on weekends. CONCLUSION There was a strong correlation between the age of participants at the time when the strains first circulated and the seroprevalence against influenza virus strains of H1N1 and H3N2. Also, age ofthe participants and the frequencies of their contacts to people, was also correlated.

目的 探討廣州市社區人群流感抗體水平與人際接觸狀況的相關性.方法採用Google數碼地圖隨機抽取廣州市行政區域範圍內研究點,受檢者接受問卷調查並抽取靜脈血檢測甲型流感(H3N2、 H1Nl)抗體. 結果 (1)Google數碼地圖隨機選取50個點中符合研究入選條件40個(856戶家庭2 801人)作為研究對象,實際參加1 821人(65.0％),鄉村和市區人群分別佔77.3％(1 407/1 821)和22.7％(414/1 821),以18～59歲年齡段為主,其次為≥60歲老年人,2～17歲組比例最低;(2)願意提供血樣者佔78.1％(1 423/1 821),H3N2和H1N1流感病毒抗體陽性率與年齡密切相關,以2～17歲年齡組最高;(3)受檢人群間皮膚或近距離人際接觸頻率甚高,每天接觸≥10人者高達49.8％ ～ 72.6％,無零接觸者,且以6～17歲組比例最高;相對於工作日,休息日接觸人數較少.結論 廣州地區社區人群H3N2和H1N1流感病毒抗體陽性率以及人際間近距離接觸頻率均與年齡有關.