We all love silver bullets. Like the vaccines for smallpox or polio. Get immunized, and you're absolutely safe. No smallpox. No polio. So when we hear the word "vaccine," we've come to think "silver bullet," and that makes the new vaccine for human papillomavirus something of a challenge.

According to the FDA, the new vaccine is nearly 100 percent effective against four of many, many HPV strains; however, two of these strains can be linked to 70% of all the cervical cancer cases in this country, some 7,000 out of 10,000 cases total. Being new, the FDA also tells us that "more studies need to be done. The FDA does not know if you will need a booster after a couple of years."

While we layman are pondering just how workable this vaccine is, we learn that the FDA has been approved it for girls age 9 through 25 and the CDC has recommended it for all girls starting at about 11 or 12.

Our "silver bullet" thinking kicks into overdrive: Not all strains? Not all cases of cervical cancer? And for only a few thousand cases, you want us to inoculate millions of young girls?

The logic is simple and abrupt. But that's not the only reason why the news of this vaccine has made headlines.

Short of some complicated technique laid out in a best-selling beach-read, the only way to spread the HPV virus is through sexual intercourse, and the idea of vaccinating a nine year old girl against something she could only contract through sexual contact is unfathomable and heartbreaking.

But now we're out of the science and into the heart of reality.

The squeaky clean families with punishing secrets. The trauma of rape. The mores of teenagers with their feelings of immortality and hormones to burn. And we lulled by media suggestive of alluring, consequence-free sex. Although we're not entirely mesmerized.

Remember the societal reaction to the partial exposure of Janet Jackson's breast during a Super Bowl half-time show? To be accurate, the nipple was well and completely covered, and there wasn't much to see. In fact, another recording artist wore a similar patch to an awards show without incident. But in that case, we all knew what was coming.

With Janet Jackson, it was the shock of what you thought you were seeing. It took several seconds to realize that there wasn't anything to see. It was all performance. The shock was in your brain. The same as if you had had the experience.

You see, I happened to be watching intently at the time, upended by the entire performance of Jackson and her dancers. Broadcast to the largest single television audience of the year - mostly male and many of whom were imbibing alcohol - was this wildly suggestive dance worthy of a strip club. I couldn't believe it.

If you had asked me in the moment, if all our young girls should be inoculated against HPV, I would have delivered a resounding "Yes."

But back to the facts: There is no silver bullet, and public health measures succeed only when they look at reality.

The current vaccine is administered with three shots over six months, and costs over $300, making it the costliest of all 16 recommended vaccinations, while 90% of people clear the virus quickly. It also apparently takes repeated assaults of the virus to cause enough change in the cervix to lead to cancer.

So, I say wait. There is much we must learn scientifically, more we can do technologically, and much more we must grapple with in terms of what is acceptable in our society.

I'm Moira Gunn. This is Five Minutes.