The effect of pair formation and variable infectivity on the spread of an infection without recovery
The effect of pair formation and variable infectivity on the spread of an infection without recovery
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DOI：
10.1016/s0025-5564(97)10008-6
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发表时间：
1998-02-01
影响因子：
4.3
通讯作者：
Dietz, K
中科院分区：
文献类型：
--
作者：
Kretzschmar, M;Dietz, K
对于没有恢复的感染传播，我们比较了一个模型的性质，其中的接触被假设为是瞬时的，每一个接触是与一个新的合作伙伴，一个明确的描述伙伴关系的形成和持续时间的模型。我们调查的动态行为，在流行病的开始，指数增长阶段和地方病平衡的人口与一个简单的人口统计过程。假设两种模型的基本再生比R-0相等，进行了比较。在第二步中，我们引入变量感染到两个模型，并研究如何与配对形成和伙伴关系持续时间的过程中相互作用。主要结果如下：如果考虑伙伴关系持续时间，则（a）流行率可能最初会下降，即使R-0 > 1;（B）指数增长率低于没有伙伴关系持续时间的模型;（c）地方病平衡高于没有伙伴关系持续时间的模型。此外，我们还证明了对于一个具有正的伙伴关系持续时间的模型，对于R-0的一个值，可能有多个相应的流行病增长率和地方病稳定态。这意味着，如果没有关于伙伴关系进程的进一步信息，就无法从地方病水平估计R-0。最后，我们证明，即使是一个非常低的值，每个接触传染性在第二阶段的感染，已经假设为HIV感染，在第二阶段的传播可能会显着贡献的流行病的传播，由于第二阶段的持续时间长。因此，如果平均伴侣关系持续时间较短，则在感染的第一阶段降低高传染性仅显著影响R-0。(C)1998年爱思唯尔科学公司All rights reserved.
For the spread of an infection without recovery we compare the properties of a model in which contacts are assumed to be instantaneous and every contact is with a new partner to a model with an explicit description of partnership formation and duration. We investigate the dynamic behaviour at the beginning of the epidemic, the exponential growth phase and the endemic equilibrium in a population with a simple demographic process. Comparisons are made with the assumption that the basic reproduction ratio R-0 is equal for both models. In a second step we introduce variable infectivity into both models and investigate how that interacts with the process of pair formation and partnership duration. The main results are: If partnership duration is taken into account, then (a) the prevalence may initially decrease, even if R-0 > 1; (b) the exponential growth rate is lower than in a model without partnership duration; (c) the endemic equilibrium is higher than in a model without partnership duration. Furthermore we show that for a model with positive partnership duration for one value of R-0 one might have more than one corresponding epidemic growth rate and endemic steady state. This implies that one cannot estimate R-0 from the endemic level without further information on the partnership process. Finally we demonstrate that even for a very low value of per contact infectivity in the second stage of infection, as has been postulated For HIV-infection, transmission during the second stage may contribute significantly to the spread of the epidemic due to the long duration of the second stage. Therefore, reduction of the high infectivity in the short first stage of infection only affects R-0 markedly if average partnership duration is short. (C) 1998 Elsevier Science Inc. All rights reserved.