Impact of cross-protective vaccines on epidemiological and evolutionary dynamics of influenza
Impact of cross-protective vaccines on epidemiological and evolutionary dynamics of influenza
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DOI：
10.1073/pnas.1113342109
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发表时间：
2012-02-21
影响因子：
11.1
通讯作者：
Grenfell, Bryan T.
中科院分区：
文献类型：
--
作者：
Arinaminpathy, Nimalan;Ratmann, Oliver;Grenfell, Bryan T.
大规模免疫接种对麻疹和天花等许多传染病的控制产生了深远影响，因为疫苗接种运动能够长期维持群体免疫，从而间接保护未接种疫苗的人。就人类流感而言，大规模疫苗接种的这种潜在益处迄今尚未得到证实。主要困难是病毒具有相当大的免疫逃逸能力；新的大流行变异体以及季节性流感中的病毒逃逸突变体损害了群体对自然感染或现有疫苗部署的免疫力的增强。因此，目前大多数流感疫苗接种规划主要侧重于保护特定风险群体，而不是大规模预防保护。在这里，我们使用流行病学模型来表明，旨在广谱保护的新兴疫苗技术可以从质量上改变这种情况。我们证明，通过潜在地降低传播率和提高群体免疫力，持续接种此类疫苗可以显著缓解流感大流行和季节性流行。更微妙的是，系统动力学模型表明，广泛的交叉保护性免疫可以减缓季节性流感的抗原进化；这些影响对向大规模预防人类流感的疫苗接种战略过渡以及对抗原性变病毒的一般管理具有深远的影响。
Large-scale immunization has profoundly impacted control of many infectious diseases such as measles and smallpox because of the ability of vaccination campaigns to maintain long-term herd immunity and, hence, indirect protection of the unvaccinated. In the case of human influenza, such potential benefits of mass vaccination have so far proved elusive. The central difficulty is a considerable viral capacity for immune escape; new pandemic variants, as well as viral escape mutants in seasonal influenza, compromise the buildup of herd immunity from natural infection or deployment of current vaccines. Consequently, most current influenza vaccination programs focus mainly on protection of specific risk groups, rather than mass prophylactic protection. Here, we use epidemiological models to show that emerging vaccine technologies, aimed at broad-spectrum protection, could qualitatively alter this picture. We demonstrate that sustained immunization with such vaccines could-through potentially lowering transmission rates and improving herd immunity-significantly moderate both influenza pandemic and seasonal epidemics. More subtly, phylodynamic models indicate that widespread cross-protective immunization could slow the antigenic evolution of seasonal influenza; these effects have profound implications for a transition to mass vaccination strategies against human influenza, and for the management of antigenically variable viruses in general.