Chao Day-Yu, Cheng Kuang-Fu, Hsieh Ying-Hen, Li Tsai-Chung, Wu Trong-Neng, Chen Chiu-Ying
Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan.
BMC Infect Dis. 2014 Jul 3;14:369. doi: 10.1186/1471-2334-14-369.
Although it has been suggested that schoolchildren vaccination reduces influenza morbidity and mortality in the community, it is unknown whether geographical heterogeneity would affect vaccine effectiveness.
A 3-year prospective, non-randomized sero-epidemiological study was conducted during 2008-2011 by recruiting schoolchildren from both urban and rural areas. Respective totals of 124, 206, and 176 households were recruited and their household contacts were followed. Serum samples were collected pre-vaccination, one-month post-vaccination and post-season from children and household contacts for hemagglutination inhibition (HI) assay. A multivariate logistic model implemented with generalized estimation equations (GEE) was fitted with morbidity or a four-fold increase in HI titer of the household contacts for two consecutive sera as the dependent variable; with geographical location, vaccination status of each household and previous vaccination history as predictor variables.
Although our results show no significant reduction in the proportion of infection or clinical morbidity among household contacts, a higher risk of infection, indicated by odds ratio>1, was consistently observed among household children contacts from the un-vaccinated households after adjusting for confounding variables. Interestingly, a statistically significant lower risk of infection was observed among household adult contacts from rural area when compared to those from urban area (OR=0.89; 95% CI: 0.82-0.97 for Year 2 and OR=0.85; 95% CI: 0.75-0.96 for Year 3).
A significant difference in the risk of influenza infection among household adults due to geographical heterogeneity, independent of schoolchildren vaccination status, was revealed in this study. Its impact on vaccine effectiveness requires further study.
尽管有研究表明在校儿童接种疫苗可降低社区内流感的发病率和死亡率，但地理异质性是否会影响疫苗效果尚不清楚。
2008年至2011年期间开展了一项为期3年的前瞻性、非随机血清流行病学研究，招募了来自城市和农村地区的在校儿童。分别招募了124、206和176户家庭，并对其家庭接触者进行随访。在接种疫苗前、接种疫苗后1个月和流感季节结束后，采集儿童及其家庭接触者的血清样本进行血凝抑制（HI）试验。以发病率或连续两份血清中家庭接触者HI滴度增加四倍作为因变量，采用广义估计方程（GEE）实施多变量逻辑模型；以地理位置、每户的疫苗接种状况和既往疫苗接种史作为预测变量。
尽管我们的结果显示家庭接触者中感染比例或临床发病率没有显著降低，但在调整混杂变量后，未接种疫苗家庭的家庭儿童接触者中始终观察到感染风险较高（比值比>1）。有趣的是，与城市地区的家庭成人接触者相比，农村地区的家庭成人接触者感染风险在统计学上显著较低（第2年的比值比=0.89；95%置信区间：0.82-0.97；第3年的比值比=0.85；95%置信区间：0.75-0.96）。
本研究揭示了家庭成人中流感感染风险因地理异质性存在显著差异，且与在校儿童疫苗接种状况无关。其对疫苗效果的影响需要进一步研究。
