Vaccines against influenza are generally administered through injections. Children are rarely given injections because parents fear for the pain their children will undergo. Consequently, the vaccination is done mostly on adults who are at risk of serious complications from influenza. Now, a new vaccine in the form of a nasal spray suitable for children has been developed. The benefit of vaccinating children using the spray is questionable because children don't typically develop serious complications from influenza and, therefore, there would not be much of a public health benefit from the widespread vaccination of children using the nasal spray.
Which of the following is an assumption on which the argument depends?