At the cat's advanced age, its immune system may not have been as adept at fending off influenza as that of a younger animal - similar to the vulnerability seen in aging humans.

当猫猫衰老后，免疫系统将不如年轻时那样能很好的抵御流感—同老年人一样。

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Fifth, it is to build safeguarding system and enhance the competence in fending off the risk.

五是建立政策保障体系，提高防范和抵御风险的能力。

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The aim is to give the body a head start in fending the virus off to stop it overpowering the immune system and taking hold.

BBC: Vaccine