4Bs Excersize

I've been having trouble with the latest exercise, with the 4Bs and deciding between type of acquisition or retention.

What I want for the hpv vaccine for men is Acquisition, Stimulate Demand. I think that's what makes the most sense for me.

Category: Vaccination, specifically hpv vaccination
Customer Definition: I still have to decide between boys aged 9-26 who already want to be vaccinated, or their parents who are making that decision who support vaccination, since the customer definition is who we want them to be, not who they are pre-our efforts. Even so, I think I will have to narrow this down.
Other Competitors: People getting false/faulty information about the vaccine
Bodies: I'll need a number here, but this will be any boy aged 9-26 who is not yet vaccinated, or parents of this age group of boys with the potential to vaccinate their kids

Beliefs:
Before: No need to vaccinate
% Converted: Hopefully 80-90% (I need to define my goal more concretely) of whatever the first cohort of girls in 5 years to get vaccinated was
After: Want hpv vaccine (for themselves if they're a boy, or for their child if they are parents)

Behaviors:
Before: Not vaccinated
Purchases/year Before: None, no hpv vaccine
% Converted: Hopefully 80% of what the number of girls was
Purchases/year After: 1-3 shots of the hpv vaccine, with my measurable goal of at least getting the initial shot
After: Vaccinated with Gardasil

Key Metric: # of customers, so boys getting the 1st shot of Gardasil in the 5 years (? or just the length of the campaign and directly after?) of study

Bucks: Well, however much the vaccine costs, which varies, but around $600 per person if they get all 3 shots, but $200 per person, as an estimate, for the first shot

When I think about acquisition and steal share, that is when it gets tricky for a vaccine where Gardasil is the only hpv vaccine in the US, so who is it stealing shares from? There is no direct competitor, but time would be an option as something that it goes against, the convenience of not going to get the vaccine. Even so, I think stimulating demand is the way to go for a new product out for a certain cohort of people.

A retention campaign would be if I wanted people to go get the 2nd and 3rd shots in the series once they already started getting the vaccination, but for now, I just want them to start, so I'll focus on acquisition.