Really depends where did you get the vaccine.
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送交者: shortstop 于 2010-02-25, 13:50:44:
回答: 我头年打疫苗，第二年体检就没抗体了 由 筋斗云 于 2010-02-24, 23:01:52:
I heard that one has to have another one after several years if got in China; but in US one needn't after completing vaccines.
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