Frequently Asked Questions About Human Papillomavirus and Cervical Cancer
From the National Cancer Institute and the Centers for Disease Control and Prevention
What are human papillomaviruses, and how are they transmitted?
Human papillomaviruses (HPV) are a group of more than 100 viruses. They are called papillomaviruses because certain types may cause warts, or papillomas, which are benign (noncancerous) tumors. The HPVs that cause the common warts which grow on hands and feet are different from those that cause growths in the throat or genital area. Some types of HPV are associated with certain types of cancer. These are called "high-risk" oncogenic or carcinogenic HPVs.
Of the more than 100 types of HPV, over 30 types can be passed from one person to another through sexual contact. Although HPVs are usually transmitted sexually, doctors cannot say for certain when infection occurred. Most HPV infections occur without any symptoms and go away without any treatment over the course of a few years. However, HPV infection sometimes persists for many years, with or without causing cell abnormalities.
How common is HPV?
At least 50% of sexually active people will get HPV at some time in their lives. Every year in the United States (U.S.), about 6.2 million people get HPV. HPV is most common in young women and men who are in their late teens and early 20s.
Anyone who has ever had genital contact with another person can get HPV. Both men and women can get it — and pass it on to their sex partners — without even realizing it.
How is HPV related to cervical cancer?
Some types of HPV can infect a woman's cervix (lower part of the womb) and cause the cells to change. Most of the time, HPV goes away on its own. When HPV is gone, the cervix cells go back to normal. But sometimes, HPV does not go away. Instead, it lingers (persists) and continues to change the cells on a woman’s cervix. These cell changes (or "precancers") can lead to cancer over time, if they are not treated.
Are there specific types of HPV that are associated with cancer?
Some types of HPV are referred to as "low-risk" viruses because they rarely develop into cancer. HPV types that are more likely to lead to the development of cancer are referred to as "high-risk." Both high-risk and low-risk types of HPV can cause the growth of abnormal cells, but generally only the high-risk types of HPV may lead to cancer. Sexually transmitted, high-risk HPVs cause growths that are usually flat and nearly invisible, as compared with the warts caused by types HPV–6 and HPV–11. It is important to note, however, that the majority of high-risk HPV infections go away on their own and do not cause cancer.
What are the risk factors for HPV infection and cervical cancer?
Having many sexual partners is a risk factor for HPV infection. Although most HPV infections go away on their own without causing any type of abnormality, infection with high-risk HPV types increases the chance that mild abnormalities will progress to more severe abnormalities or cervical cancer. Still, of the women who do develop abnormal cell changes with high-risk types of HPV, only a small percentage would develop cervical cancer if the abnormal cells were not removed. Studies suggest that whether a woman develops cervical cancer depends on a variety of factors acting together with high-risk HPVs. The factors that may increase the risk of cervical cancer in women with HPV infection include smoking and having many children.
Can HPV infection be prevented?
The surest way to eliminate risk for genital HPV infection is to refrain from any genital contact with another individual.
For those who choose to be sexually active, a long-term, mutually monogamous relationship with an uninfected partner is the strategy most likely to prevent genital HPV infection. However, it is difficult to determine whether a partner who has been sexually active in the past is currently infected.
HPV infection can occur in both male and female genital areas that are covered or protected by a latex condom, as well as in areas that are not covered. Although the effect of condoms in preventing HPV infection is unknown, condom use has been associated with a lower rate of cervical cancer.
In June 2006, the Advisory Committee on Immunization Practices (ACIP) voted to recommend the first vaccine developed to prevent cervical cancer and other diseases in females caused by certain types of genital human papillomavirus (HPV). The vaccine, Gardasil®, protects against four HPV types, which together cause 70% of cervical cancers and 90% of genital warts. The vaccine is given through a series of three shots over a 6-month period. The second and third doses should be given 2 and 6 months (respectively) after the first dose.
How are HPV infections detected?
Testing samples of cervical cells is an effective way to identify high-risk types of HPV that may be present. The FDA has approved an HPV test as a follow-up for women who have an ambiguous Pap test (a screening test to detect cervical cell changes and, for women over the age of 30, for general cervical cancer screening). This HPV test can identify 13 of the high-risk types of HPV associated with the development of cervical cancer. This test, which looks for viral DNA, is performed by collecting cells from the cervix and then sending them to a laboratory for analysis. The test can detect high-risk types of HPV even before there are any conclusive visible changes to the cervical cells. There are currently no tests approved to detect HPV infection in men.
What are the treatments for HPV infection?
Although there is currently no medical cure for papillomavirus infection, the lesions and warts these viruses cause can be treated. Methods commonly used to treat lesions include cryosurgery (freezing that destroys tissue), LEEP (loop electrosurgical excision procedure, the removal of tissue using a hot wire loop), and conventional surgery. Similar treatments may be used for external genital warts. In addition, some drugs may be used to treat external genital warts. More information about treatment for genital warts can be found on the Centers for Disease Control and Prevention's (CDC) Sexually Transmitted Diseases Treatment Guidelines.
Who should get the HPV vaccine?
The HPV vaccine is recommended for 11-12 year-old girls, and can be given to girls as young as 9. A catch-up vaccine is also recommended for 13-26 year-old girls/women who have not yet received or completed the vaccine series. (Research on the vaccine's safety and effectiveness in women older than age 26 has only recently begun.)
These recommendations have been proposed by the ACIP — a national group of experts that advises the CDC on vaccine issues. These recommendations are now being considered by the CDC.
Ideally, females should get the vaccine before they are sexually active. This is because the vaccine is most effective in girls/women who have not yet acquired any of the four HPV types covered by the vaccine. Girls/women who have not been infected with any of those four HPV types will get the full benefits of the vaccine.
Will sexually active females benefit from the vaccine?
Females who are sexually active may also benefit from the vaccine. But they may get less benefit from the vaccine since they may have already acquired one or more HPV type(s) covered by the vaccine. Few young women are infected with all four of these HPV types. So they would still get protection from those types they have not acquired. Currently, there is no test available to tell if a girl/woman has had any or all of these four HPV types.
Will girls and women who have been vaccinated still need cervical cancer screening?
Yes. There are three reasons why women will still need regular cervical cancer screening. First, the vaccine will NOT protect against all types of HPV that cause cervical cancer, so vaccinated women will still be at risk for some cancers. Second, some women may not get all required doses of the vaccine (or they may not get them at the right times), so they may not get the vaccine’s full benefits. Third, women may not get the full benefit of the vaccine if they receive it after they’ve already acquired one of the four HPV types.
Should girls and women be screened before getting vaccinated?
No. Girls/women do not need to get an HPV test or Pap test to find out if they should get the vaccine. An HPV test or a Pap test can tell that a woman may have HPV, but these tests cannot tell the specific HPV type(s) that a woman has. Even girls/women with one HPV type could get protection from the other vaccine HPV types they have not yet acquired.
Will the vaccine be covered by insurance plans?
While some insurance companies may cover the vaccine, others may not. Most large insurance plans usually cover the costs of recommended vaccines. However, there is often a short lag-time after a vaccine is recommended, before it is available and covered by health plans. The retail price of the vaccine is $120 per dose ($360 for full series). Some states also provide free or low-cost vaccines at public health department clinics to people without health insurance coverage for vaccines.