Plans to raise the issue at the World Health Assembly in May 2009 were pre-empted by the H1N1 influenza pandemic and hopes have refocused on this year's upcoming Assembly.
The H1N1 pandemic was characterized by the emergence of a new influenza virus to which many people had no pre-existing immunity.
H1N 1流感大流行的特点是出现新的流感病毒，而许多人对其并没有预先存在的免疫力。
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If the findings from these studies are real they raise important questions about the biological interactions between pre-existing and novel pandemic influenza strains.