State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Microbiology and Epidemiology, People's Republic of China.
Am J Epidemiol. 2012 May 1;175(9):890-7. doi: 10.1093/aje/kwr411. Epub 2012 Apr 5.
Data from all reported cases of 2009 pandemic influenza A (H1N1) were obtained from the China Information System for Disease Control and Prevention. The spatiotemporal distribution patterns of cases were characterized through spatial analysis. The impact of travel-related risk factors on invasion of the disease was analyzed using survival analysis, and climatic factors related to local transmission were identified using multilevel Poisson regression, both at the county level. The results showed that the epidemic spanned a large geographic area, with the most affected areas being in western China. Significant differences in incidence were found among age groups, with incidences peaking in school-age children. Overall, the epidemic spread from southeast to northwest. Proximity to airports and being intersected by national highways or freeways but not railways were variables associated with the presence of the disease in a county. Lower temperature and lower relative humidity were the climatic factors facilitating local transmission after correction for the effects of school summer vacation and public holidays, as well as population density and the density of medical facilities. These findings indicate that interventions focused on domestic travel, population density, and climatic factors could play a role in mitigating the public health impact of future influenza pandemics.
从中国疾病预防控制信息系统获取了所有报告的 2009 年大流行性流感 A（H1N1）病例数据。通过空间分析描述了病例的时空分布模式。使用生存分析分析了与旅行相关的风险因素对疾病侵袭的影响，并使用多层次泊松回归在县级确定了与本地传播相关的气候因素。结果表明，该疫情波及的地理区域很大，受影响最严重的地区在中国西部。各年龄组的发病率存在显著差异，学龄儿童的发病率最高。总体而言，疫情从东南向西北蔓延。靠近机场，以及与国道或高速公路交叉但不与铁路交叉，是与一个县存在该疾病相关的变量。经校正学校暑假和节假日、人口密度以及医疗设施密度的影响后，较低的温度和较低的相对湿度是有利于本地传播的气候因素。这些发现表明，针对国内旅行、人口密度和气候因素的干预措施可能有助于减轻未来流感大流行对公共卫生的影响。
