That is true, i hadn't thought about that. A very good and valid point. What a dilemma!
I guess we can either do as Gamdwelf say and not vaccinate some (or all) of our children, although that can be risky, or we can rely on future science to keep evolving just as the viruses does. A very tricky situation indeed, i'll get back to you when i have more info before i make an opinion.