一道Assumption题，是属于有gap的还是没有gap的

until now, only injectable vaccines against influenza have been available. Parents are reluctant to subject  children to the pain of injection, but adults, who are at risk of serious complications from influenza, are commonly vaccinated. A new influenza vaccine, administered painlessly in a nasal spray, is effective for children. However, since children seldom develop serious complications from influenza, no significant public health benefit would result from widespread vaccination of children using the nasal spray.

这是一个assumption题的题干（来自XDF）。我只想问一下这个事有Gap的assumption题还是没有gap的？

我个人觉得应该是没有gap的。请高人指点（最好能说一下你的分析思路）。谢谢。

怎么没有人回答呢？哪位高手可以指点一下。分析assumption题是否有gap，我一直都觉得很模糊，希望NN给些建议。谢谢了。