When the HPV vaccine was first introduced, there were a number of reasons people listed for being critical. Some were just corporate cynicism - a company that just lost $5 billion in a Vioxx settlement was working its way under the same vaccine halo as polio and smallpox, they said. Others argued that it didn't work very well. And then there was a more subjective cultural claim that protecting teenage girls against a future cancer by making sex seem safer would lead to promiscuity.The good news on the first two is that there have been no issues. Though we doubled the costs to get new drugs to market in response to high-profile lawsuits, we are no more safe, and no less safe, than we were 20 years ago. And the modern HPV vaccine (Gardasil 9) is highly effective, providing almost 100 percent protection from HPV types 6, 11, 16, 18, 31, 33, 45, 52 and 58. Ten years later they are still working, with no end in sight.What about promiscuity? Did teenage girls suddenly rush to have sex because it was safer? Sorry teenage boys, it didn't work that way . In 2008, British Columbia began an HPV vaccination program in schools for girls in grades 6 and 9 and three years later changed it to just girls in grade 6. Surveys of over 300,000 girls conducted in 7th and 12th grades every five years have shown no uptick in teenage sex since the 2008 HPV program. Instead, it went down, from 21.3 percent in 2003 to 18.3 percent in 2013. Use of condoms also went up over four percent.Maybe awareness of diseases decreased sexual activity? When I was a kid, herpes was the big fear. Then AIDS came along and cold sores looked darn good by comparison. Everyone was in a panic. Is it plausible that greater awareness of human papillomavirus caused young people to be more cautious?