Skepticism, Science & Pseudoscience

Of course cervical cancer doesn't generally manifest itself until women are what, in their 30s or later? So obviously the only way we're going to see what effect Gardasil really has is to wait until those who got the initial shots get to that age.

But getting back to your question, you can't argue with them. Just point out the facts to anyone who might see the discussion, and move on.