同时，虽说年轻人是流感的易感人群，但一旦感染，最可能需要住院治疗或有生命危险的，主要还是幼儿、孕妇、病人和老人。

Also, although the flu infects younger people, the ones most likely to need hospitalization or die if they do get infected are the very young, pregnant women, the sick and the aged.

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发病时他的免疫细胞只有40多个，现在只有26个，而正常人水平都在500个以上，虽然现在看上去都很健康，但一旦感染就非常危险。

Incidence of immune cells, he is only more than 40, now only 26, while the normal level at 500 or more, although it is now looks very healthy, but once the infection is very dangerous.

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但艾滋病病毒感染者一旦发病即成为艾滋病病人，常常伴有低热、腹泻等症状，或有合并感染等病症。

However, once HIV becomes AIDS disease patients, often accompanied by low heat, symptoms such as diarrhea, infection or disease, and so on.

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