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

2009年的流感大流行突显了科学家和政府监测流感的一些切实问题。到目前为止，他们已经统计了去他们的医生或医院出现流感样症状的人数。但这并不能告诉我们轻微的病例。轻微的病例之所以重要，是因为有一种叫做“群体免疫”的东西。在任何疫情期间，当没有足够的易感人群来维持疫情的火种时，新病例的数量就会开始下降。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，为了能够了解流感疫情可能有多大，我们还需要测量轻微的病例。如果我们抽取血液并检测抗体，我们就可以做到这一点。在这个项目中，我们希望测试在20世纪90年代末和21世纪初被丢弃的匿名血液样本中的流感。通过对这些旧样本进行10个或数千个测试，我们可以确切地看到轻微病例的数据对未来的流行病可能有多大帮助，我们可以回答关于不同流感毒株的有趣问题。在20世纪90年代末和21世纪初，有三种不同类型的流感流行。两种甲型流感和一种B型流感，其中两种目前仍在传播(A/H3N2型和B型)。其中一人被大流行毒株(A/H1N1)取代。我们想要比较和对比这三种类型。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一种流行病会发生，或者像它原来那样大，而不仅仅是描述它。我们可以看看重要的基本问题，比如：B型流感是否没有A型流感那么严重；如果你感染了轻微的流感，你可能会比感染严重的人更快地再次感染？

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?