Understanding herd immunity for influenza using archived sera from the UK and mathematical models

2009年的流感大流行凸显了科学家和政府如何监测流感的一些实际问题。到目前为止，他们已经统计了有流感样症状去看医生或医院的人数。但这并没有告诉我们轻微病例的情况。轻微病例很重要，因为有一种叫做“群体免疫”的东西。在任何流行病期间，当没有足够的易感人群来保持流行病的“火”时，新病例的数量开始下降。有轻微症状或没有症状的人与有症状的人一样擅长阻止疫情。因此，为了能够了解流感流行的规模，我们也需要测量轻微病例。如果我们抽血并检测抗体，我们就能做到这一点。在这个项目中，我们想测试在20世纪90年代末和21世纪初丢弃的匿名血液样本。通过对这些旧样本进行成千上万次的测试，我们可以确切地看到轻微病例的数据对未来的流行病有多有用，我们可以回答关于不同流感菌株的有趣问题。在20世纪90年代末和21世纪初，有三种不同类型的流感在流行。有两种A型流感和一种B型流感，其中两种（A/H3N2和B型）目前仍在传播。其中一个被大流行毒株（A/H1N1）所取代。我们要比较和收缩这三种类型。我们将使用数学模型来分析血液测试的数据。模型帮助我们弄清楚为什么流行病会发生，或者为什么会如此之大，而不仅仅是描述它。我们可以看看一些重要的基本问题，比如：乙型流感的感染程度是否比甲型流感轻；如果你感染了轻微的流感，你再次感染的速度会比严重感染的速度更快？

The 2009 pandemic highlighted some real problems with how scientists and governments monitor influenza. Up-to-now, they have counted numbers of people who go to their doctor or the hospital with flu-like symptoms. But this doesn't tell us about the mild cases.Mild cases are important because of something called 'herd immunity'. During any epidemic, the number of new cases starts to go down when there are not enough susceptible people to keep 'the fire' of the epidemic going. People with mild or no symptoms are just as good at stopping the epidemic as people with symptoms. So, to be able to understand how big an influenza epidemic might be, we need to measure mild cases as well.We can do this if we take blood and test for antibodies. In this project, we want to test anonymous blood samples for influenza that were discarded in the late 1990s and early 2000s. By doing 10s of 1000s of tests on these old samples, we can see exactly how useful the data on mild cases might be for future epidemics and we can answer interesting questions about different influenza strains. There were three different types of influenza circulating in the late 1990s and early 2000s. Two types of influenza A and one was influenza B. Two of those three are still circulating now (A/H3N2 and B). One of them was replaced by the pandemic strain (A/H1N1). We want to compare and contract these three types.We will use mathematical models to analyze the data from the blood tests. Models help us to figure out why an epidemic occurred or was as big as it was, rather than just describing it. We can look at important basic questions like: is flu B less serious infection that influenza A; and if you get a mild infection of flu you can get infected again more quickly than if you get a serious infection?