This was because the pandemic virus spread faster than would be expected if there were widespread immunity to it, and because antibodies to the seasonal vaccine do not cross-react with it.

这是因为大流行病毒比预料传播更为迅速，即使对它有普遍免疫性，季节疫苗的抗体与它也没有交叉作用。

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When people have no pre-existing immunity to a flu virus, they need not just one but two doses of vaccine several weeks apart - making it very hard to immunise many people in time to protect them.

当人们对流感病毒没有预先免疫性，他们就需要几周间隔的两次注射而不是一次注射-这在当时免疫接种很多人去保护他们操作是非常困难的。

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It is learnt that the adenovirus type 5 (common cold virus) has immunity volunteers a higher risk of HIV infection, the flu virus is the key to AIDS vaccine components.

据悉，对5型腺病毒(普通感冒病毒)具有免疫力的志愿者感染HIV的几率更高，这种感冒病毒是该艾滋病疫苗的关键组成部分。

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In 1957, when flu swept through Hong Kong, Mr Hilleman identified the virus as a new form to which people had no natural immunity and passed on his findings to vaccine-makers.

ECONOMIST: Obituary