Harnessing Case Isolation and Ring Vaccination to Control Ebola
Harnessing Case Isolation and Ring Vaccination to Control Ebola
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DOI：
10.1371/journal.pntd.0003794
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发表时间：
2015-05-01
影响因子：
3.8
通讯作者：
Galvani, Alison P.
中科院分区：
文献类型：
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作者：
Wells, Chad;Yamin, Dan;Galvani, Alison P.
随着西非毁灭性埃博拉疫情的持续，正在实施包括接触者追踪、隔离和病例隔离在内的非药物控制措施。此外，公共卫生机构正在加大力度测试和部署候选疫苗。鉴于疫苗的实验性和最初供应有限，大规模疫苗接种运动可能不可行。然而，对可能的病例接触者进行环形接种可作为分发疫苗的一种有效替代方法。为了评估环形疫苗接种作为消除埃博拉的策略，我们建立了埃博拉传播的对近似模型，以利比里亚和塞拉利昂2014年6月至2015年1月的确诊发病率数据为参数。我们的研究结果表明，如果在2014年初秋启动病例隔离和环形疫苗接种的联合干预措施，那么除了单独隔离病例外，利比里亚和塞拉利昂最多可避免126例病例和560例病例。在人均接触者较多、个体间聚集性较强、接触者追踪效力较低或接种疫苗可提供暴露后保护的情况下，环形疫苗接种的边际效益预计最大。在这种情况下，环形疫苗接种最多可避免8%的埃博拉病例。因此，预计环形疫苗接种将为正在进行的非药物埃博拉控制工作提供适度有益的补充。
As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.