Taking a risk with a vaccine in order to protect third parties is an issue i find personally repugnant and a wonderful sales method.
I take full responsibility for my own health and would never ever ask a third party to risk a vaccine for my benefit or my childrens as i think it morally stinks.
Unfortunately, due to their crass stupidity and selfishness, that herd immunity can no longer be relied on.
Truth Seeker's argument also falls down when you consider the effect of the MMR vaccine. It protects the recipient directly. It's not a case of "take this to help others" - it's a case of "take this to help yourself"; herd immunity is the natural long term outcome.
Herd immunity protects the weaker members of society - the very young, and those with medical conditions which prevent them being able to take the MMR vaccine themselves. For anyone to state that they're not willing to have that as a side effect of a vaccine that helps them is just vile - the attitude of someone who'd not call 999 for an ambulance for a road accident victim, due to worries about running their credit down.