I think they should be offered the opportunity for councellling to make their own decision concerning the jabs. A 15 year old is certainly Gilick competant to decide whether she has the MMR and I suspect the eleven year old is as well.
These children need information to make up their own minds. They can always CHOOSE to have the MMR at a later date.
"No I think they should be vaccinated. I don't think it is fair for other people to be put at risk of deadly diseases because of the whims of a parent."
Their position is no different to the thousands of parents up and down the country who have chosen not to vacinate.