Don't forget that this was so those teenagers can have massive amounts of unprotected, premarital sex with random people.
https://www.cdc.gov/std/hpv/stdfact-hpv.htm > You can get HPV by having vaginal, anal, or oral sex with someone who has the virus. It is most commonly spread during vaginal or anal sex. It also spreads through close skin-to-skin touching during sex.