Well the only thing I can think of is that HPV might have a role that we don't know about yet in... something we don't know about yet.

Otherwise, vaccines are a pretty well-understood technology.

I generally agree with Lisa SH that pharm companies are a powerful lobby, and that this decision to make the vaccine mandatory (can anyone post a link to information about this "mandatory" thing?????) might be no stranger to that.

However it's also common to give a given vaccine to everyone of a generation so that the disease is eradicated. But then boys should get it too, since they will keep transmitting it. By vaccinating only girls, aren't we perpetuating the problem (and making an eternal market for the vaccine)?