Implications of partial immunity on the prospects for tuberculosis control by post-exposure interventions
Implications of partial immunity on the prospects for tuberculosis control by post-exposure interventions
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DOI：
10.1016/j.jtbi.2007.06.005
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发表时间：
2007-10-21
影响因子：
2
通讯作者：
Medley, Graham F.
中科院分区：
文献类型：
--
作者：
Gomes, M. Gabriela M.;Rodrigues, Paula;Medley, Graham F.
目前，世界三分之一的人口（约 20 亿人）感染了结核分枝杆菌，其中绝大多数为潜伏感染。由于一生中重新激活的风险约为 10%，因此其中 2 亿人最终将患上活动性肺部疾病。只有治疗或暴露后干预才能控制这一巨大的感染库。治疗潜伏感染可以降低再感染的风险，并且越来越多的证据表明，与暴露后疫苗联合使用可以降低再感染的风险。在这里，我们开发数学模型来探索这些暴露后干预措施在全球范围内控制结核病的潜力。针对近期感染的强化计划似乎总体上有效，但在中等流行情况下，其益处可能更大。在流行率较低的情况下，将这些策略扩展到长期持续感染似乎更有益。最后，我们认为治疗会改变对再感染的易感性，并探讨其流行病学后果。当我们假设治疗可以降低随后再感染的易感性时，就会观察到灾难性的动态。因此，获得了双相结果，其中患病率水平小幅或大幅降低，具体取决于潜伏感染的检测和治疗率。相比之下，治疗后易感性增加可能会导致疾病患病率增加，但不会导致灾难性的动态。除非实施广泛的干预，否则这些潜在的结果是沉默的。 (C) 2007 Elsevier Ltd. 保留所有权利。
One-third of the world population (approximately 2 billion individuals) is currently infected with Mycobacterium tuberculosis, the vast majority harboring a latent infection. As the risk of reactivation is around 10% in a lifetime, it follows that 200 million of these will eventually develop active pulmonary disease. Only therapeutic or post-exposure interventions can tame this vast reservoir of infection. Treatment of latent infections can reduce the risk of reactivation, and there is accumulating evidence that combination with postexposure vaccines can reduce the risk of reinfection. Here we develop mathematical models to explore the potential of these postexposure interventions to control tuberculosis on a global scale. Intensive programs targeting recent infections appear generally effective, but the benefit is potentially greater in intermediate prevalence scenarios. Extending these strategies to longer-term persistent infections appears more beneficial where prevalence is low. Finally, we consider that susceptibility to reinfection is altered by therapy, and explore its epidemiological consequences. When we assume that therapy reduces susceptibility to subsequent reinfection, catastrophic dynamics are observed. Thus, a bipolar outcome is obtained, where either small or large reductions in prevalence levels result, depending on the rate of detection and treatment of latent infections. By contrast, increased susceptibility after therapy may induce an increase in disease prevalence and does not lead to catastrophic dynamics. These potential outcomes are silent unless a widespread intervention is implemented. (C) 2007 Elsevier Ltd. All rights reserved.