HPV vaccine FAQ's
Frequently Asked Questions About Human Papilloma Virus (HPV) Vaccines
SOURCE: American Cancer Society
An HPV vaccine is now available. Below is general information about HPV as well as information about this new vaccine.
What are viruses? Viruses are very small organisms -- most cannot even be seen with an ordinary microscope. They cannot reproduce on their own; they must enter a living cell, which becomes the host cell, and "hijack" the cell’s machinery to make more viruses.
Viruses can enter the body through the nose, mouth, or breaks in the skin. Once inside, they find their specific type of host cell to infect. For example, cold and flu viruses specifically attack cells that line the respiratory or digestive tracts. The human immunodeficiency virus (HIV) infects the T-cells and macrophages of the immune system. HPV infects squamous epithelial cells in the body.
What is HPV?
HPV is short for human papilloma (pap-ah-LO-mah) virus. HPVs are a group of over 100 related viruses. Each HPV virus in the group is given a number, which is called an HPV type. HPVs are called papilloma viruses because some of the HPV types cause warts, or papillomas, which are non-cancerous tumors. The papilloma viruses are attracted to and are able to live only in squamous epithelial cells in the body. Squamous epithelial cells are thin, flat cells that are found on the surface of the skin, cervix, vagina, anus, vulva, head of the penis, mouth, and throat. HPVs will not grow in other parts of the body.
Of the more than 100 strains of HPV, about 60 HPV types cause warts on non-genital skin, such as on the hands and feet. These are the common warts.
The other 40 HPV types are mucosal types of HPV. "Mucosal" refers to the body’s mucous membranes, or the moist skin-like layers that line organs and cavities of the body that open to the outside. For example, the vagina and anus have a moist skin-like layer. The mucosal HPV types are also called the genital (or anogenital) type HPVs because they typically affect the anal and genital area. The mucosal HPVs prefer the moist squamous cells found in this area. They do not prefer the skin of the hands and feet.
Some types of genital HPVs can cause cauliflower-shaped warts to appear on or around the genitals and anus of both men and women. In women, visible warts may also appear on the cervix and vagina. This type of "genital wart" is known technically as condyloma acuminatum and is most often caused by HPV-6 or HPV-11. Because these genital warts rarely develop into cancer, HPV-6 and HPV-11 are called "low-risk" viruses. These low-risk types can also cause low-grade cervix cell changes that do not develop into cancer.
Other genital type HPVs have been linked with genital or anal cancers in both men and women. They also cause low and high-grade cervix cell changes and pre-cancers. These are called "high-risk" HPV types and include HPV-16, HPV-18, HPV-31, HPV -35, HPV-39, HPV-45, HPV-51, HPV-52, and HPV-58, as well as some others.
How do you get HPV?
Genital HPV is transmitted mainly by direct genital contact during vaginal or anal intercourse. It is not spread through bodily fluids, nor does it live in blood, or any organs.
Infection is very common soon after a woman becomes sexually active. In one recent study, more than 50% of college age women were found to have acquired an HPV infection within 4 years of first having sex.
Transmission by genital contact without intercourse is not common, but infection has been reported in women who did not have a history of intercourse. Oral-genital and hand-genital transmission of some genital HPV types is possible and has been reported. Transmission from mother to newborn during delivery is rare. When it occurs it can lead to development of warts in the infant’s throat called respiratory papillomatosis.
How common is HPV? Who gets it?
HPV is a very common virus. Some doctors think it is almost as common as the common cold virus. In the United States, over 6 million people get an HPV infection every year. Almost half of the infections are in those between 15 and 25 years of age. About half to three-fourths of the people who have ever had sex will have HPV at some time in their life.
What are the symptoms of HPV?
HPV usually has no symptoms, unless it is a type that causes genital warts. Genital warts may occur within weeks or months after contact with a partner who has HPV. More rarely, genital warts may occur years after exposure.
Most people will never know if they have HPV because no significant disease develops and the immune system suppresses the virus. A small percent of people with HPV will have the virus for a longer time and will develop cell changes that may lead over many years to cervical or other anogenital cancer.
How is HPV related to cervical cancer?
Almost all (>99 percent) cervical cancers are related to HPV. Of these, about 70 percent are caused by HPV types 16 or 18. About 500,000 pre-cancerous cell changes of the cervix, vagina, and vulva are diagnosed each year in the US, and over half are related to HPV 16 and 18. Low-grade cervix cell changes are caused by a variety of HPV types, including 16, 18, 6, or 11.
Although nearly all cervical cancers are related to HPV, most genital HPV infections do not cause cervical cancer. Most people who test positive for genital HPV DNA in research studies eventually test negative, often within 6 to 12 months. Scientists are still not sure whether this means that a person’s immune system has completely destroyed all of the HPV or has only suppressed the infection to an extremely low level (too low to be detected by available tests). If even a few cells of the cervix still contain HPV, it’s possible that the virus may start to become active again if your immune system becomes very weakened.
It is possible that some low-grade cervix cell changes and some high-grade cervix cell changes may suddenly occur many years after first HPV exposure. This could help explain how a woman could get such changes after many years of normal Pap tests and no history of a partner change.
If the HPV infection isn’t eliminated or suppressed, the virus may cause cervix cells to change and become pre-cancer cells. True pre-cancer cell changes are called high-grade SIL (squamous intraepithelial lesions), sometimes abbreviated as HSIL. Another term for HSIL is CIN 2 and CIN3. CIN is an abbreviation for cervical intraepithelial neoplasia.
Pre-cancer cells are not cancer. Although some pre-cancer changes may return to normal on their own, most cases of CIN 3 are likely to progress to cervical cancer over a period of time that probably takes about 10 years if not detected and treated. But very few HPV infections lead to cervical cancer. Pre-cancer cells are found by having regular Pap tests.
For more information on cervical cancer, please see the American Cancer Society document, “Cervical Cancer.”
What about other cancers and HPV?
About 80 percent of squamous cell anal cancers are caused by either HPV 16 or 18. At least 40 percent of cancers of the vulva are HPV-related. Several other anogenital cancers (penile, vaginal, urethral) and some head and neck cancers (specifically tongue and tonsils) have been found to contain high-risk HPV types. A high percentage of non-melanoma skin cancers in people with weakened immune systems contain HPV types.
What about other HPV-related diseases?
Over 500,000 new cases of anogenital warts are diagnosed yearly in the United States, and over 90% are caused by HPV types 6 or 11. Juvenile respiratory papillomatosis occurs in about 1 in 200,000 infants and children and may lead to respiratory problems or rarely progress to cancer of the larynx. HPV types 6 and 11 are most frequently found with this condition.
Do men have HPV-associated cancers?
Men and women share this virus. Therefore, HPV is likely to be as common in men as in women. But HPV is not as easily diagnosed in men as in women, so the infection rate of HPV in men is always more of an estimate than it is in women. Genital HPV is passed to men through vaginal and anal sex -- the same way as in women. Certain types of HPV have been linked to penile and anal cancer in men. While penile cancer is rare, anal cancer is now almost as common in men and women who have anal sex as cervical cancer was in women before the Pap test was introduced.
Men do not have symptoms with HPV unless it is the type that causes genital warts. In men, genital warts can appear around the anus, or on the penis, scrotum, groin or thighs.
There is no test approved to detect HPV in men. But genital warts can be detected and treated. There are no tests approved to detect early HPV-related cancers in men, as there is in women with the Pap test. In gay, bisexual, and HIV-positive men, some doctors use anal Pap tests to detect and treat precancerous changes of the anus. Since the use of anal testing is in the early stages of development, the impact on anal cancer rates will not be seen for many years in the future. For more information on sexually transmitted illnesses in men, please contact ASHA at http://www.ashastd.org, or http://www.iwannaknow.org (Teen sexual health education services), or http://www.quierosaber.org (Spanish teen sexual health education services).
Can HPV be treated?
Treatments cannot cure HPV. However, most genital HPV infections go away with the help of the body’s immune system. Seventy percent (70%) of HPV infections are typically gone within one year and 90% are gone within 2 years. Treatments are available for genital warts, for the pre-cancer cell changes that HPV can cause, and for cervical and other HPV-associated anogenital cancers.
Can HPV be prevented?
The only sure way to prevent HPV is to abstain from all sexual activity. Limiting the number of sexual partners and avoiding sex with people who have had many other sexual partners decreases risk of exposure to HPV. It is usually not possible to know who has HPV, and HPV infection is so very common that even these measures do not guarantee that a person will not get HPV. These measures are likely, however, to reduce the number of HPV exposures over one’s life.
Condoms provide some (but not total) protection against HPV. They also are very helpful in protecting from other infections that can be spread through sexual activity.
What are the risk factors for genital HPV?
Having many sexual partners is a risk factor for HPV infection. The risk increases with the number of partners. Also, being younger than 25 years of age, starting to have sexual intercourse at age 16 or younger, and having a male partner who has had several different sex partners increase the risk.
Is there a vaccine to prevent HPV?
In June, 2006 the US Food and Drug Administration (FDA) approved an HPV vaccine, which is now being shipped to health care centers. This vaccine protects against 2 types of HPV that cause 70% of all cervical cancers (HPV 16 and 18) and 2 types of HPV that cause 90% of all genital warts (HPV 6 and 11). The other types of HPV will NOT be prevented by use of the vaccine.
Did the American Cancer Society play a role in the development of the HPV vaccine?
Yes. Dr. Robert Rose at University of Rochester was a member of one of four teams that contributed to the development of a vaccine against HPV. The grant he received from the American Cancer Society in the mid-1990s enabled him to continue and confirm his important work studying the virus.
Is the HPV vaccine safe?
The HPV vaccine has been tested in thousands of people in many countries around the world. There appear to be no serious side effects. The most common side effect is brief soreness at the injection site. The FDA had determined that the vaccine is safe and effective for females aged 9 to 26 years.
Who should be vaccinated and when?
To be most effective, the HPV vaccine should be given before a person becomes sexually active, and in 3 doses within one year. The Federal Advisory Committee on Immunization Practices (ACIP) has recommended that the vaccine be routinely given to females aged 11 to 12 and as early as age 9 years at the discretion of doctors. The committee also recommended women ages 13 to 26 who have not yet been vaccinated receive "catch-up" vaccinations. The American Cancer Society also recommends that the vaccine be routinely given to females aged 11 to 12 and as early as age 9 years at the discretion of doctors. The independent panel making the Society recommendations concluded there was insufficient evidence of benefit to recommend catch-up vaccination of all women age 19 to 26 years. As a result, the Society recommends “catch-up” vaccinations for females ages 13 to 18 only, and that women aged 19 to 26 talk to their health care provider about whether to get the vaccine, based on the risk of previous HPV exposure and potential benefit from vaccination.
The panel’s conclusion regarding insufficient evidence is based on several factors: (1) The women who participated in the vaccine studies had, on average, two sexual partners in their lifetime, and none of the women had more than four partners. Women aged 19-26 years in this country have an average of 3-4 lifetime sexual partners, and many women have more than 4 lifetime partners, so the findings from the clinical trials may not represent the US population. The risk of HPV exposure increases with each lifetime sexual partner. (2) The clinical trials showed that the vaccine prevented nearly all precancers (CIN2 and CIN3) caused by HPV-16 and HPV-18. However, the vaccine prevented less than half of all precancers (caused by any type of HPV). This suggests that the vaccine may not be very effective among women who are already sexually active. (3) Recommendations for new medical tests and vaccines consider information on whether they will be cost-effective. This takes into account t he cost of the vaccine as well as the benefits. HPV vaccination is cost-effective for girls at age 11-12. However, there is a lack of cost-effectiveness analyses for catch-up vaccination of women ages 19-26.
Will boys get this vaccine?
Boys were included in part of the studies to see if it was safe in boys and to see if boys’ immune systems responded to the vaccine. The vaccine did prove safe and boys did have an immune response to the vaccine. It is not known at this time if it will protect boys from warts or from transmitting HPV to their partners which would also reduce cervical cancer. Studies are being done to determine if the vaccine is effective in preventing HPV infection and genital warts in boys.
What are the benefits of the vaccine?
The vaccine will provide protection against the HPVs that cause about 70% of cervical cancers and most (90%) genital warts, in women who have not been exposed to the types of HPV that are in the vaccine. The vaccine will not protect against or treat infections in women who have already had an infection with HPV-16, -18, -6, and/or -11. The vaccine also could protect against some other HPV-related cancers, including some anal, vulvar, and vaginal cancers, as well as some head and neck cancers. It will be many years before it can be proven to protect against any of these cancers.
How long will the vaccine protect against HPV infection?
How long a new vaccine protects people is never known when the vaccine is first introduced. Research is being done to find out how long protection against HPV will last, and if a booster vaccine will be needed.
How much will HPV vaccines cost? Will they be covered by insurance plans?
The catalog price is $120 per dose and 3 doses over one year are needed. This cost does not include the cost for giving the injections or the doctor’s charge. It is expected that insurance plans will cover the cost in accordance with ACIP recommendations. However, there may be a lag time before the vaccine’s approval and when it is covered by health plans. The ACIP also voted to recommend that the HPV vaccine be included in the federal Vaccine for Children (VFC) entitlement program, which covers vaccine costs for children and teens who do not have insurance and for some children and teens who are underinsured. The VFC program provides free vaccines to children and adolescents younger than 19 years of age, who are either Medicaid-eligible, American Indian, or Alaska Native or uninsured. There are over 45,000 sites that provide VFC vaccines, including hospital, private, and public clinics. The VFC Program also allows children and adolescents to get VFC vaccines through Federally Q ualified Health Centers or Rural Health Centers, if their private health insurance does not cover vaccinations. For more information about the VFC, visit:
www.cdc.gov/vaccines/programs/vfc/default.htm.
Will girls/women who have been vaccinated still need Pap tests?
Because the vaccine will NOT provide protection against all of the types of HPV that can cause cervical cancer, women will still need Pap tests.
Can cervical cancer be prevented without a vaccine?
Pap tests given according to American Cancer Society guidelines, and proper follow-up, will prevent most but not all cases of cervical cancer, and will detect most but not all cervical cancers at an early, curable stage. Most cervical cancers in the United States are diagnosed in women who have never had a Pap test, or who haven’t had a Pap test in 5 or more years. If all sexually active women had regular Pap tests, most cervical cancers could be prevented.
Is the American Cancer Society in favor of vaccinating against HPV?
The Society is very much in favor of vaccinating against HPV. The Society will be actively involved in providing credible and unbiased information to the public and to health care providers, with an emphasis on the continued need to follow screening guidelines, such as getting regular Pap tests; and on the critical need to ensure that the vaccine is available to the medically underserved.
What is the Society doing to promote the vaccine’s use?
The Society is engaged in an active public education effort to ensure broad public awareness and acceptance of the new vaccine, recognizing the importance of building and sustaining the infrastructure to support successful implementation of the vaccine program.
When will the vaccine be available?
The vaccine is available in some doctors' offices and clinics, and will become more widely available in 2007.
For easy reading information on HPV and cervical cancer:
What Every Woman Should Know About Cervix Cancer and HPV
Thinking AboutTesting for HPV?
