The current swine flu H3N2 viruses are closely related to human H3N2 viruses.

H3N2病毒一开始是从人身上传染到猪的，现在的H3N2猪流感病毒与H3N2人流感病毒有着很近的相关性。

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But because H3N2 completely replaces H2N2 in people, no one born since 1968 has any immunity to H2.

但因为H3N2在人体完全取代H2N2所以在1968年之后出生的人没有一个人对H2有任何免疫性。

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The antibodies that had protected a lot of Europeans the previous winter no longer worked against this "drifted" strain of H3N2.

在上一个冬季保护了很多欧洲人的抗体已经无法抵抗这种“漂移”的病毒株h3n2。

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But as this figure from the CDC shows, the current season has been dominated by H3N2.

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That includes the 2007-08 and 2003-04 seasons, which also saw a predominant H3N2 strain.

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And this year we had a big spike in deaths due to flu, all because of H3N2.

FORBES: Has the Swine Flu Disappeared?