Implications of vaccination and waning immunity
Implications of vaccination and waning immunity
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DOI：
10.1098/rspb.2009.0057
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发表时间：
2009-06-07
影响因子：
4.7
通讯作者：
Keeling, M. J.
中科院分区：
文献类型：
--
作者：
Heffernan, J. M.;Keeling, M. J.
对于免疫可以提供终身保护的传染病，可以使用各种简单的模型来解释疫苗接种作为控制方法的效用。然而，对于许多疾病，免疫力会随着时间的推移而减弱，随后因无症状感染而增强（增强）。对此类流行病学过程的研究需要一个模型制定，该模型可以捕获病原体和免疫系统的宿主内动态以及相关的人群水平传播动态。在这里，我们对这样一个麻疹模型进行参数化，并展示疫苗接种如何产生一系列意想不到的后果，因为它会降低免疫力的自然增强并减少幼稚易感者的数量。特别是，我们表明，适度的衰退时间（40-80 年）和高水平的疫苗接种（大于 70%）可以引发大规模振荡，在高峰期产生大量有症状的病例。此外，我们预测，在长期无病期之后，感染的引入将导致比标准模型预测的规模大得多的流行病。这些结果对于任何疫苗接种运动的长期成功都有明显的影响，并强调需要充分了解免疫和疫苗接种的免疫机制。
For infectious diseases where immunization can offer lifelong protection, a variety of simple models can be used to explain the utility of vaccination as a control method. However, for many diseases, immunity wanes over time and is subsequently enhanced ( boosted) by asymptomatic encounters with the infection. The study of this type of epidemiological process requires a model formulation that can capture both the within-host dynamics of the pathogen and immune system as well as the associated population-level transmission dynamics. Here, we parametrize such a model for measles and show how vaccination can have a range of unexpected consequences as it reduces the natural boosting of immunity as well as reducing the number of naive susceptibles. In particular, we show that moderate waning times (40-80 years) and high levels of vaccination ( greater than 70%) can induce large-scale oscillations with substantial numbers of symptomatic cases being generated at the peak. In addition, we predict that, after a long disease-free period, the introduction of infection will lead to far larger epidemics than that predicted by standard models. These results have clear implications for the long-term success of any vaccination campaign and highlight the need for a sound understanding of the immunological mechanisms of immunity and vaccination.