Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
The Bill and Melinda Gates Foundation, Seattle, Washington, United States of America.
PLoS One. 2017 Oct 11;12(10):e0185577. doi: 10.1371/journal.pone.0185577. eCollection 2017.
Since the introduction of polio vaccines in the 1950's and 60's, eradication of poliovirus from the world has been technically feasible. Progress towards this goal, however, has been uneven and influenced by social and political factors that challenge the implementation of robust immunization programs. While violence and insecurity are often cited as barriers to eradication, current global risk models are largely based on virologic and immunologic indicators measured at national levels. In this manuscript, we quantify the relevance of indicators of violence and insecurity on the risk of polio spread.
Using logistic regression models and public data sources, we evaluate the relationship between measures of violence and instability and the location of poliomyelitis cases between 2006 and 2015 at the country-level, both individually and after controlling for more proximal determinants of disease, such as nearby circulating poliovirus and vaccination rates. We found that increases in a country's Fragile States Index (FSI) and Global Peace Index (GPI), aggregate indicators of violence and instability, were associated with the occurrence of poliovirus cases in the subsequent year (p< 0.01), even after controlling for established risk factors. These effects of violence and insecurity must be mediated through immunity and exposure to poliovirus, coarse measures of which are included in our model. This also implies that in our study, and in risk models in general, the interpretation depends on the quality and granularity of available data.
National virologic and immunologic indicators understate the risk of poliovirus spread in areas with violence and insecurity, and the inclusion of such factors improves precision. In addition, the link between violence and incidence of disease highlights the broader challenge of implementing health interventions in conflict areas. We discuss practical implications of this work in understanding and measuring the risks to polio eradication and other global health initiatives, and the policy implications of the need to reach vulnerable populations in conflict zones.
自 20 世纪 50 年代和 60 年代引入脊髓灰质炎疫苗以来，从世界范围内根除脊髓灰质炎病毒在技术上已经可行。然而，在实现这一目标的过程中，进展并不均衡，受到社会和政治因素的影响，这些因素对实施强有力的免疫规划构成了挑战。虽然暴力和不安全通常被认为是根除的障碍，但当前的全球风险模型主要基于在国家层面测量的病毒学和免疫学指标。在本文中，我们量化了暴力和不安全指标对脊髓灰质炎传播风险的相关性。
我们使用逻辑回归模型和公共数据源，评估了 2006 年至 2015 年期间，在国家层面上，暴力和不稳定措施与脊髓灰质炎病例位置之间的关系，包括单独评估和在控制疾病更接近的决定因素（如附近循环的脊髓灰质炎病毒和疫苗接种率）之后的评估。我们发现，一个国家的脆弱国家指数（FSI）和全球和平指数（GPI）的增加，这两个暴力和不稳定的综合指标与下一年脊髓灰质炎病毒病例的发生有关（p<0.01），即使在控制了已确立的风险因素之后也是如此。这些暴力和不安全的影响必须通过免疫和暴露于脊髓灰质炎病毒来介导，而我们的模型中包含了这些病毒的粗略衡量指标。这也意味着，在我们的研究中，以及在一般的风险模型中，解释取决于可用数据的质量和粒度。
在暴力和不安全地区，国家病毒学和免疫学指标低估了脊髓灰质炎病毒传播的风险，而纳入这些因素可以提高精度。此外，暴力与疾病发病率之间的联系突出了在冲突地区实施卫生干预措施所面临的更广泛挑战。我们讨论了这项工作在理解和衡量脊髓灰质炎根除和其他全球卫生倡议风险方面的实际意义，以及在冲突地区接触弱势群体的必要性所带来的政策意义。
