广播电视英语短句 第 219 课：小儿麻痹症-3

This has led to greater use of monovalent vaccines to protect against either type one or type three polio. 此举致使人们大范围使用单价疫苗预防 一型和二型 （第一种和第三种）小儿麻痹病毒。

But Carol Pandak says the monovalent vaccine is not enough in areas with both. 不过， Carol Pandak 说单价疫苗还不足以应付 同一地区 兼有两种病毒。

Rod Curtis at the World Health Organization in Geneva says the new bivalent vaccine solves this problem. 日内瓦世界卫生组织的 Rod Curties 表示新的二价疫苗可以解决这一问题。

Carol Pandak says tests found the new vaccine to be thirty percent more effective than the trivalent vaccine. Carol Pandak 说测试发现新疫苗比三价疫苗的功效高出 30% 。