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The FDA has approved Gardasil, a vaccine that targets the virus responsible for most cervical cancers and genital warts. Here are 12 questions and answers on the new vaccine.

1. What is Gardasil?

Gardasil is a vaccine that targets four strains of human papillomavirus (HPV). Those strains are called HPV-6, HPV-11, HPV-16, and HPV-18.

Related Story: Cervical Cancer Vaccine Wins Federal Approval

HPV-16 and HPV-18 account for about 70% of all cervical cancers. Cervical cancer is cancer of the cervix, which connects the vagina to the uterus.

HPV-6 and HPV-11 account for about 90% of genital warts.

The vaccine is also approved to help prevent vaginal and vulvar cancers, which can also be caused by HPV.

2. How does HPV spread?

HPV is spread through sex. HPV infection is common. About 20 million people in the U.S. are infected with HPV, and by age 50, at least 80% of women will have had an HPV infection, according to the CDC.

Most women with HPV infection don't develop cervical cancer.

3. Does Gardasil protect against all cervical cancers?

No. Though the vaccine protects against leading causes of cervical cancer, it doesn't ward off other causes of cervical cancer.

4. How effective is Gardasil?

Studies have shown 100% effectiveness in protecting against infection with HPV-16 and HPV-18 strains in people who had not been previously exposed to the virus.

5. How long does Gardasil last?

Tests show that the vaccine lasts at least four years. Long-term results aren't known yet.

6. Does the vaccine contain a live virus?
No. Gardasil contains a virus-like particle, but not the virus itself.

7. Who should get the vaccine?

The FDA approved Gardasil for girls and women aged 9-26. The FDA's decision doesn't automatically make the vaccine part of the CDC's recommended vaccine schedule. The company that makes Gardasil is continuing to research use of the vaccine in boys and men, as they can also become infected with HPV, which could lead to genital warts.

8. Is Gardasil safe?

Reports from clinical trials, to date, show Gardasil to be safe.

9. Will Gardasil protect women from cervical cancer who've already been exposed to HPV?

Gardasil is not designed to protect people who've already been exposed to HPV.

10. Will the new vaccine eliminate the need for cervical cancer screening?

No. Gardasil doesn't protect against all causes of cervical cancer, so screening (such as the Pap test) will still be needed. Screening is essential to detect cancer and precancerous lesions caused by other HPV types. Screening will also continue to be necessary for women who have not been vaccinated or are already infected with HPV.

11. Are there other cervical cancer vaccines?

Gardasil is the first cervical cancer vaccine to be approved. In fact, it's the first vaccine to protect against a risk factor for a cancer. Another cervical cancer vaccine, called Cervarix, is also in the works. It's expected to be submitted for approval by the end of 2006.

12. How many people get cervical cancer and die from the disease?

About 9,710 cases of invasive cervical cancer will be diagnosed in the U.S. in 2006, predicts the American Cancer Society.

About 3,700 U.S. women will die of cervical cancer in 2006, according to the American Cancer Society.

Worldwide, cervical cancer is a leading cause of cancer deaths for women. According to the FDA there are 470,000 new cases and 233,000 deaths each year.

Reviewed by Michael W. Smith, MD

SOURCES: WebMD Medical News: "Cervical Cancer Vaccine Approved." WebMD Medical Reference: "Understanding Cervical Cancer: The Basics." American Cancer Society: "What Are the Key Statistics About Cervical Cancer?" World Health Organization: "Comprehensive Cancer Control: A Guide to Essential Practice." CDC: "Cervical Cancer Awareness: Human Papillomavirus (HPV)." News release, Merck. FDA.