来自《耶鲁大学开放课程：生物医学工程探索 第10集 第10集》

• 
  
  This curve here with the square shows you
  这个带方形的曲线图显示了
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  how many millions of
  在美国数以百万计的
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  vaccine doses were distributed across the U.S.
  疫苗是如何使用的
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  so this is hundreds of millions of doses that were given.
  数据显示已有数亿支疫苗被注射
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  As those doses were given
  随着疫苗的使用
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  you look at the prevalence of polio within the United States.
  你可以看到全美小儿麻痹症
• 
  
  It dropped dramatically
  患病率在一九五四年后的
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  in the period from 1954--
  一段时间里急剧下降
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  this is these filled black bars refer to this axis,
  该坐标轴上的这些黑色柱形图表明
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  polio cases per 100,000 population dropped down
  到一九五六年 小儿麻痹症的发病率
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  to only three or four cases by 1956.
  已经降低至每十万人中仅三到四人发病
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  So, this just shows as the vaccine was distributed,
  因此 这表明随着疫苗的推广