Pathogen transmission from vaccinated hosts can cause dose-dependent reduction in virulence
Pathogen transmission from vaccinated hosts can cause dose-dependent reduction in virulence
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DOI：
10.1371/journal.pbio.3000619
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发表时间：
2020-03-01
期刊：
影响因子：
9.8
通讯作者：
Doeschl-Wilson, Andrea
中科院分区：
文献类型：
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作者：
Bailey, Richard I.;Cheng, Hans H.;Doeschl-Wilson, Andrea
许多牲畜和人类疫苗是漏水的，因为它们阻止了症状，但无法防止感染或进一步传播。这种泄漏令人担忧，因为它增加了预防疾病传播所需的疫苗接种覆盖率，并可以促进病原体毒力增强的进化。尽管存在泄漏，但接种疫苗可能会减少病原体载量，影响疾病传播动态。然而，对传播后疾病发展和接触者传染性的影响尚不清楚。在这里，我们使用涉及马立克氏病病毒(MDV)在鸡中的传播实验来表明，接种泄漏疫苗大大降低了接种疫苗个人和未接种疫苗接触者感染的病毒载量。因此，接触过的禽类在被接种疫苗的禽类感染时，不太可能出现疾病症状或死亡，表现出不那么严重的症状，自身释放的传染性病毒也更少。这些结果突出表明，即使部分接种漏水的疫苗，在控制疾病的传播和症状方面也可能产生意想不到的积极后果。
Many livestock and human vaccines are leaky because they block symptoms but do not prevent infection or onward transmission. This leakiness is concerning because it increases vaccination coverage required to prevent disease spread and can promote evolution of increased pathogen virulence. Despite leakiness, vaccination may reduce pathogen load, affecting disease transmission dynamics. However, the impacts on post-transmission disease development and infectiousness in contact individuals are unknown. Here, we use transmission experiments involving Marek disease virus (MDV) in chickens to show that vaccination with a leaky vaccine substantially reduces viral load in both vaccinated individuals and unvaccinated contact individuals they infect. Consequently, contact birds are less likely to develop disease symptoms or die, show less severe symptoms, and shed less infectious virus themselves, when infected by vaccinated birds. These results highlight that even partial vaccination with a leaky vaccine can have unforeseen positive consequences in controlling the spread and symptoms of disease.