Department of Applied Mathematics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (SAR) China.
Department of Biostatistics, School of Public Health, University of Texas Health Science Center at Houston, United States.
Sci Rep. 2017 Jan 9;7:40085. doi: 10.1038/srep40085.
We studied the spatio-temporal patterns of the proportions of influenza B cases out of all typed cases, with data from 139 countries and regions downloaded from the FluNet compiled by the World Health Organization, from January 2006 to October 2015. We restricted our analysis to 34 countries that reported more than 2,000 confirmations for each of types A and B over the study period. Globally, we found that Pearson's correlation is greater than 0.6 between effective distance from Mexico and the proportions of influenza B cases among the countries during the post-pandemic era (i.e. Week 1, 2010 to Week 40, 2015). Locally, in the United States, the proportions of influenza B cases in the pre-pandemic period (2003-2008) negatively correlated with that in the post-pandemic era (2010-2015) at the regional level. Our study limitations are the country-level variations in both surveillance methods and testing policies. The proportions of influenza B cases displayed wide variations over the study period. Our findings suggest that the 2009 influenza pandemic has an evident impact on the relative burden of the two influenza types. Future studies should examine whether there are other additional factors. This study has potential implications in prioritizing public health control measures.
我们研究了 2006 年 1 月至 2015 年 10 月期间，来自世界卫生组织 FluNet 汇编的 139 个国家和地区的数据中，流感 B 型病例在所有分型病例中所占比例的时空模式。我们将分析仅限于在研究期间报告 A 型和 B 型确诊病例均超过 2000 例的 34 个国家。在全球范围内，我们发现，大流行后时期（即 2010 年第 1 周至 2015 年第 40 周），墨西哥有效距离与各国流感 B 型病例比例之间的皮尔逊相关系数大于 0.6。在局部地区，在美国，大流行前时期（2003-2008 年）流感 B 型病例比例与大流行后时期（2010-2015 年）呈负相关，这在区域水平上有所体现。我们研究的局限性在于监测方法和检测政策在国家层面上存在差异。在研究期间，流感 B 型病例的比例存在广泛变化。我们的研究结果表明，2009 年流感大流行对两种流感类型的相对负担有明显影响。未来的研究应该检查是否存在其他额外的因素。这项研究对优先考虑公共卫生控制措施具有潜在意义。
