HPV — the human papilloma virus — is a very common sexually transmitted infection that affects millions of women and men around the world.

Most types of genital HPV cause no symptoms. A few types cause genital warts, which may be uncomfortable and unattractive, but are not dangerous. A few other types of genital HPV, however, can lead to cancer of the cervix, anus, penis, vagina, and vulva.  All types usually pass through the system without doing any harm.  But if some of the high-risk types persist, that can cause cancer.

Fortunately, two drug companies have developed vaccines that protect against the types of HPV that most commonly produce symptoms — a development that could save hundreds of thousands of lives. One is available for girls now.

But there's a catch and a controversy: The vaccine is most effective when given to girls before sexual activity with partners begins — as early as nine to 12 years of age.

While most people agree that vaccinating young people against HPV is an important step in protecting them against cancer, some are opposing the vaccine, claiming that it would give young people "permission" to have sex.

The Lowdown on HPV and Cancer

HPV is spread through skin-to-skin contact. There are more than 100 types of HPV, and about 40 of these types affect the genitals and reproductive organs. About 20 million people in the United States are currently infected with genital HPV. In fact, it's so common that about half of sexually active women and men have genital HPV infection at some point in their lives.

Some types of genital HPV cause genital warts, which can be annoying, but are harmless. And while most HPV infections resolve of themselves, a few types of HPV, if they persist, can cause cell changes that can lead to cancer of the cervix, anus, penis, vagina, and vulva.

Worldwide, cervical cancer alone strikes half a million women and claims 270,000 lives each year, making it the third-leading cancer killer among women, after breast cancer and lung cancer. (Fewer women die of cervical cancer in the U.S. than in other parts of the world because they are more likely to rely on Pap tests for early detection of precancerous conditions.)

The Vaccine

In a major sexual health breakthrough, the drug company Merck has developed a vaccine — Gardisil — that is nearly 100 percent effective against HPV 16 and 18, the two types of HPV that account for 70 percent of cervical cancers. It is also effective against two types of HPV that cause genital warts.

Another drug company, GlaxoSmithKline, has created a vaccine that is not yet on the market. It will protect against the same two high-risk types of HPV.

Stand Up for Your Sexual Health

If you want to make your voice heard on this issue, there's a lot you can do to educate and influence people on local, state, and national levels. Here are a few suggestions to get started:

  • Create a list of messages that you want to express, and share them — with your family, friends, teachers, mentors, and neighbors — during casual conversation. You can start the dialogue by saying, "I just read an article about HPV vaccines. What do you think about that issue?" Then tell them what you learned and your points of view.
  • Contact your local newspaper, radio, and television networks. Send them a letter or e-mail sharing your perspective as a teen, and help raise awareness in your community about HPV vaccines.
  • Take action by sending a letter or e-mail to elected officials voicing your support for HPV vaccines. Visit the Planned Parenthood Action Network to find out the contact information for your local, state, and federal officials.

Vaccinating young people is the surest way to protect against HPV and prevent cervical and genital cancers. People who are sexually active should still reduce their risk of getting HPV by using condoms every time they have sex. In addition, women who are sexually active, whether vaccinated or not, can protect themselves against cervical cancer by getting regular Pap tests.