I'm convinced that anyone who opposes the vaccine is a monster.
Their arguments basically all hinge on the idea that giving girls the vaccine removes consequences of sex and thus "encourages" casual, unprotected sex.
Except that:
1. You can get it even if you wear a condom.
2. There is no test for men.
3. It can have serious and potentially life-changing long term effects on women, including sterility and cancer.
4. You can get it from someone with whom you are in a committed, monogamous relationship, even if that person has had sex with only one other person. The virus doesn't distinguish between "casual" and "occasional" sex.
The only way to prevent it, really, is for only virgins to have sex with each other and never move on from their relationships once they've had sex.
And really, if you think about it, it's just insane to have a cure for a serious illness yet be opposed to distributing that cure.
Did they explain the 1/3 vaccinated vs the 56% drop?
I don't think it was explained directly, but I would assume it has something to do with reducing the number of "mass infectors;" people who get the virus somehow and then have sex with lots and lots of people after. Or who have sex with someone who has sex with lots of people. I remember a few years ago someone did a study on sex partners in a high school and while most people had only had sex with one or two other people, there were a few "hubs" (aka sluts, and I use that term in a gender-neutral fashion) who bagged a whole bunch of others.