The result demonstrated that the immune selective pressure only had selective function, but not the creating - mutation function in the mutation of virus.

本研究结果显示，抗体这一免疫压力在病毒的变异中可能只起选择性作用，而不起促进变异的作用。

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The second mechanism is a more gradual process of adaptive mutation, whereby the capability of the virus to bind to human cells increases during subsequent infections of humans.

第二种机制是一个渐进的适应性变异过程，在这一过程中，伴随人类受到感染，病毒与人体细胞相结合的能力增加了。

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To date, no links between the small number of patients infected with the mutated virus have been found and the mutation does not appear to spread.

迄今为止，尚未发现少数感染变异病毒的患者之间有任何联系，变异病毒似未传播开来。

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The World Health Organisation said this week it had found no evidence of mutation in the virus that had caused the latest Indonesian deaths.

ECONOMIST: Down with the flu | The

The reason for that is that the influenza virus has a rapid rate of mutation, forcing companies that manufacture the vaccine to make their best guess as to which flu types will be more prevalent in a given season.

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