However, experts are uncertain as to what constitutes an infective dose when it comes to influenza viruses.

然而，专家们也不能确定多少流感病毒能让人感染。

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However, experts are uncertain as to what constitutes an infective dose when it comes to influenza viruses.

然而，专家们也不能确定多少流感病毒能让人感染。

youdao