Quantifying the Value of Perfect Information in Emergency Vaccination Campaigns.
Quantifying the Value of Perfect Information in Emergency Vaccination Campaigns.
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DOI：
10.1371/journal.pcbi.1005318
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发表时间：
2017-02
影响因子：
4.3
通讯作者：
Tildesley MJ
中科院分区：
文献类型：
--
作者：
Bradbury NV;Probert WJ;Shea K;Runge MC;Fonnesbeck CJ;Keeling MJ;Ferrari MJ;Tildesley MJ
口蹄疫在非流行国家的爆发可能导致巨大的经济成本和牲畜损失，但疫苗接种的使用一直存在争议，部分原因是紧急口蹄疫疫苗接种的不确定性。信息值方法可以应用于疾病爆发问题，如口蹄疫，以研究解决不确定性的性能改善。在这里，我们计算的预期值解决疫苗的效力，免疫接种后的时间延迟和每日疫苗接种能力的一个假设的口蹄疫爆发在英国的不确定性。如果有可能在引入控制之前解决所有不确定性，我们可以预期节省5500万英镑的疫情成本，扑杀221，900头牲畜和4.3天的疫情持续时间。发现所有疫苗接种策略均优于仅剔除策略。然而，最佳的疫苗接种半径被认为是高度依赖于所有管理目标的疫苗接种能力。我们计算，通过解决疫苗接种能力的不确定性，无论管理目标如何，我们预计将返回上述节省的85%以上。有可能在疫情爆发前解决每日疫苗接种能力的不确定性，这将使决策者能够通过仔细的应急计划选择最佳控制行动。在英国，2001年爆发了口蹄疫（FMD），造成经济损失约80亿英镑，并导致约700万头牲畜被扑杀。控制这一流行病的主要方法是禁止流动和扑杀受感染和高风险的牲畜。口蹄疫疫苗是可用的，但没有使用，因为担心它们的有效性和它们的使用将如何影响英国的无病状态。使用沃里克FMD模型，我们在英国模拟了FMD爆发，包括环形疫苗接种作为一种爆发控制方法，具有不同水平的疫苗效力，疫苗接种和授予免疫力之间的时间延迟，以及疫苗接种能力。我们应用价值的信息分析，这些结果，并发现，在确定最佳的疫苗接种策略的最重要的因素是知识的疫苗接种能力。相比之下，从决策的角度来看，疫苗效力和疫苗接种与免疫之间的延迟相对不重要。这项工作可以为应急计划提供信息，从而在未来发生口蹄疫疫情时节省成本，也可以应用于其他传染病。
Foot-and-mouth disease outbreaks in non-endemic countries can lead to large economic costs and livestock losses but the use of vaccination has been contentious, partly due to uncertainty about emergency FMD vaccination. Value of information methods can be applied to disease outbreak problems such as FMD in order to investigate the performance improvement from resolving uncertainties. Here we calculate the expected value of resolving uncertainty about vaccine efficacy, time delay to immunity after vaccination and daily vaccination capacity for a hypothetical FMD outbreak in the UK. If it were possible to resolve all uncertainty prior to the introduction of control, we could expect savings of £55 million in outbreak cost, 221,900 livestock culled and 4.3 days of outbreak duration. All vaccination strategies were found to be preferable to a culling only strategy. However, the optimal vaccination radius was found to be highly dependent upon vaccination capacity for all management objectives. We calculate that by resolving the uncertainty surrounding vaccination capacity we would expect to return over 85% of the above savings, regardless of management objective. It may be possible to resolve uncertainty about daily vaccination capacity before an outbreak, and this would enable decision makers to select the optimal control action via careful contingency planning. In the UK during 2001 there was an outbreak of foot-and-mouth disease (FMD) which cost the economy an estimated £8 billion and led to the culling of approximately 7 million livestock. The main methods used to control the epidemic were movement bans and culling of infected and high-risk livestock. FMD vaccines were available but not used because of concerns about their effectiveness and how their use would affect the UK’s disease-free status. Using the Warwick FMD model, we ran simulations of FMD outbreaks in the UK including ring vaccination as a method of outbreak control with varying levels of vaccine efficacy, time delay between vaccination and conferral of immunity, and vaccination capacity. We applied value of information analysis to these results and found that the most important factor in determining the optimal vaccination strategy was knowledge of the vaccination capacity. In contrast, vaccine efficacy and delay between vaccination and immunity were relatively unimportant from a decision making perspective. This work could inform contingency planning that would lead to cost savings in the event of a future FMD outbreak and could also be applied to other infectious diseases.