IMO the issue is children & schools are the perfect combination for the spread of illnesses. While no one wants to make definitive statements on how much the vaccine reduces the duration & level of contagiousness -> it is almost certainly not 0%.

I think as long as the vaccine is an option for all/most ages then it isn't much of an issue. Although it would be interesting if we allowed kids to get the vaccine at school - possibly without parental permission. (Sort of a tricky area... I think some places provide the HPV vaccine like this since some parents won't let their kids get it.)