Infection, reinfection, and vaccination under suboptimal immune protection: epidemiological perspectives
Infection, reinfection, and vaccination under suboptimal immune protection: epidemiological perspectives
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DOI：
10.1016/j.jtbi.2004.02.015
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发表时间：
2004-06-21
影响因子：
2
通讯作者：
Medley, GF
中科院分区：
文献类型：
--
作者：
Gomes, MGM;White, LJ;Medley, GF
传染病的SIR（易感-感染-耐药）和SIS（易感-感染-易感）框架已得到广泛研究和成功应用。它们隐含地假设了宿主免疫反应可能范围的上限和下限。然而，大多数感染并不属于这两种极端类别。我们结合了跨越这一范围的两种一般途径：临时免疫保护（自感染后免疫力随着时间的推移而减弱）和部分免疫保护（免疫力不是完全保护，但降低了再次感染的风险）。与SIR和SIS相比，我们对这些模型的动力学和平衡特性进行了系统分析，并分析了疫苗接种计划的结果。我们描述了免疫力的减弱如何缩短了疫情间期，并给疾病根除带来了重大困难。当包括部分免疫时，我们确定了传播中的“再感染阈值”。在再感染阈值以下，原发性感染占主导地位，感染水平低，疫苗接种非常有效（约为SIR模型）。在再感染阈值以上，再感染占主导地位，感染水平高，疫苗接种不起保护作用（大约是SIS情况）。高感染率与疫苗接种失败之间的这种联系强调了在高负担地区控制反复感染的问题。然而，比自然感染产生更好保护的疫苗有可能增加再感染阈值，因此在最需要减少感染的地方构成具有惊人高能力的干预措施。(C) 2004 Elsevier Ltd.版权所有。
The SIR (susceptible-infectious-resistant) and SIS (susceptible-infectious-susceptible) frameworks for infectious disease have been extensively studied and successfully applied. They implicitly assume the upper and lower limits of the range of possibilities for host immune response. However, the majority of infections do not fall into either of these extreme categories. We combine two general avenues that straddle this range: temporary immune protection (immunity wanes over time since infection), and partial immune protection (immunity is not fully protective but reduces the risk of reinfection). We present a systematic analysis of the dynamics and equilibrium properties of these models in comparison to SIR and SIS, and analyse the outcome of vaccination programmes. We describe how the waning of immunity shortens inter-epidemic periods, and poses major difficulties to disease eradication. We identify a "reinfection threshold" in transmission when partial immunity is included. Below the reinfection threshold primary infection dominates, levels of infection are low, and vaccination is highly effective (approximately an SIR model). Above the reinfection threshold reinfection dominates, levels of infection are high, and vaccination fails to protect (approximately an SIS situation). This association between high prevalence of infection and vaccine failure emphasizes the problems of controlling recurrent infections in high-burden regions. However, vaccines that induce a better protection than natural infection have the potential to increase the reinfection threshold, and therefore constitute interventions with a surprisingly high capacity to reduce infection where reduction is most needed. (C) 2004 Elsevier Ltd. All rights reserved.