Key Points

• Human papillomaviruses (HPVs) are a group of more than 150 related viruses, certain types of which can cause cancer.

• The Food and Drug Administration-approved vaccines Gardasil® and Cervarix® are highly effective in preventing infection with certain types of HPV.

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• HPV vaccination has the potential to reduce cervical cancer deaths around the world by as much as two-thirds, and to prevent anal cancer in males and females. Gardasil can also prevent genital warts.

What are human papillomaviruses?

Human papillomaviruses (HPVs) are a group of more than 150 related viruses. They are called papillomaviruses because certain types may cause warts, or papillomas, which are benign (noncancerous) growths. Some types of HPV are associated with certain types of cancer. These are called “high-risk,” oncogenic, or carcinogenic HPVs.

Of the more than 150 types of HPV, more than 40 types can be passed from one person to another through sexual contact. Transmission can occur in the genitals, anal, or oral regions. Although HPVs are usually transmitted sexually, doctors cannot say for certain when infection occurred.

About 6 million new genital HPV infections occur each year in the United States. Most HPV infections occur without any symptoms and go away without any treatment over the course of a few years. However, HPV infections sometimes persist for many years, with or without causing detectable cell abnormalities.

What kinds of cancer are related to HPV infection?

Infection with high-risk HPV is the major cause of cervical cancer. Almost all women will have an HPV infection at some point, but very few will develop cervical cancer. The immune system of most women will usually suppress or eliminate HPVs. Only HPV infections that are persistent (do not go away over many years) can lead to cervical cancer.

In 2011, more than 12,000 women in the United States are expected to be diagnosed with cervical cancer and more than 4,000 are expected to die from it.1 Nearly half a million women develop cervical cancer each year worldwide, and more than a quarter of a million die from it.

High-risk HPV types also cause most anal cancers. Although anal cancer is uncommon, more than 5,000 men and women in the United States are expected to be diagnosed with the disease in 2011 and 770 people are expected to die because of it.1

Infection with high-risk HPV is also known to cause some cancers of the oropharynx, vulva, vagina, and penis.2,3