What are viruses?
Viruses are very small organisms – most cannot even be seen with a regular 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 mucous membranes, such as the nose, mouth, the lining of the eyes, or the genitals. Some enter through the digestive system (such as stomach or intestine), through insect bites, or through breaks in the skin. A few can enter unbroken skin. Once inside, they find their specific type of host cell to infect. For example, cold and flu viruses find and invade cells that line the respiratory tract (nose, sinuses, breathing tubes, and lungs). HIV (the virus that causes AIDS) infects the T-cells and macrophages of the immune system. HPV infects squamous epithelial cells – the flat cells that cover the surface of the skin and mucous membranes.
What is HPV?
HPV is short for human papilloma virus. HPVs are a group of more than 150 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. But some types of HPV are known for causing cancer, especially of the cervix (the base of the womb at the top of the vagina).
The papilloma viruses are attracted to and are able to live only in certain cells called squamous epithelial cells. These cells are found on the surface of the skin and on moist surfaces (called mucosal surfaces) like:
The vagina, anus, cervix, vulva (around the outside of the vagina)
The inner foreskin and urethra of the penis
Inner nose, mouth, throat
Trachea (the main breathing tube or windpipe), bronchi (smaller breathing tubes branching off the trachea)
The inner eyelids.
Of the more than 150 known strains, about 3 out of 4 (75%) HPV types are called cutaneous because they cause warts on the skin. Sites for warts are the arms, chest, hands, and feet. These are common warts; they are not the genital type of wart.
The other 25% of the HPV types are considered mucosal types of HPV. “Mucosal” refers to the body’s mucous membranes, or the moist surface layers that line organs and cavities of the body that open to the outside. For example, the mouth, vagina, and anus have this moist mucosal layer. The mucosal HPV types are also called the genital (or anogenital) type HPVs because they often affect the anal and genital area. The mucosal (genital) HPVs prefer the moist squamous cells found in this area. Mucosal HPV types generally don’t grow in the skin or parts of the body other than the mucosal surfaces. Here we are talking about the mucosal or genital types of HPV.The various types of HPV are often classified into low and high risk according to their association with cancer. The "low-risk" types are rarely associated with cancer. The "high-risk" types are more likely to lead to the development of cancer. Although certain types of HPV are associated with cancer, the development of HPV related cancer is considered a rare event.
What is the link between HPV infection and cancer?
Persistent HPV infection, with high risk types, is the major cause of over 99% of cervical cancers. Infection with high-risk HPV types has also been found to be an important cause of anal cancer. HPV can also play a role in the development of cancers of the penis and oropharynx (in the throat, at the back of the mouth). Both anal and penile cancers are rare in Canada, but the rates of anal cancer are increasing. Anal cancers are found at high rates in HIV positive men and women and men who have sex with men.
Can HPV be treated?
Although there is no cure for HPV infection, warts, lesions and precancerous and cancerous changes caused by the viruses can be managed and/or treated. No treatment guarantees that the HPV infection is no longer present in the body.
Some treatments for anogenital warts, such as cryotherapy (freezing the warts), are done in a clinic or doctor's office while other treatments, such as prescription creams, can be used at home. Repeat treatments are often necessary. Just because you can no longer see the wart does not mean the HPV infection is gone - the virus may still be present which means you could develop warts again without being re-exposed to the virus. For most people, warts will clear on their own over time.
The lesions and precancerous changes caused by high risk types of HPV can be treated if a health care provider feels that it is necessary. A large number of these infections will clear without any treatment. Only a small number of high risk persistent infections will progress to cancer. As with many other cancers, early detection is one of the key factors to successful treatment.
Discuss treatment options with a health care professional to determine which treatment choice may be best for you. People who are immunocompromised, especially those who are HIV-positive, may require special care.
How can you protect yourself from getting HPV?
While condoms do not eliminate the risk of HPV infection, using a condom, consistently and properly during vaginal, anal and oral sex decreases the chances of getting HPV or passing it on to your partner. You need to remember that a condom can only protect the area it covers, so it may be possible to become infected by any uncovered warts (e.g., on the scrotum). Using a condom will also help to protect you from other sexually transmitted infections and reduce the chances of unintended pregnancies.
Other ways to reduce your risk of infection include delaying sexual activity (waiting until you are older), limiting your number of sex partners and considering your partners' sexual history as this can create a risk to yourself (e.g., if they have had multiple previous partners).
There are now two HPV vaccines authorized for use in Canada: Gardasil® and Cervarix®.
Gardasil® provides protection against four HPV types: two that cause approximately 70 per cent of all cervical cancers (HPV-16, HPV-18) and two that cause approximately 90 per cent of all anogenital warts in males and females (HPV-6, HPV-11). It is approved for use in females and males aged 9 to 26.
Cervarix® provides protection against the two HPV types that cause approximately 70 per cent of all cervical cancers (HPV-16 and HPV-18). It has been approved for use in females aged 10 to 25.
How is HPV treated?
There is no treatment for the virus itself, but the body's immune system is usually able to fight it off within a few years. There are treatments, however, for the diseases the virus causes. Genital warts can be removed using chemicals, by freezing them or burning them off electrically, or via surgery or lasers. For most people, this treatment will clear the warts. If warts return repeatedly, a health practitioner may try injecting them with the drug interferon. Untreated genital warts can disappear on their own, stay the same, or grow in size and number and cluster in large masses.
Precancerous growths on the cervix can be treated in a variety of ways, from cryosurgery that freezes and destroys abnormal cells to surgical removal of problem tissue. Catching cervical changes early is the key to avoiding cervical cancer, which is more difficult to treat.
How can HPV be prevented?
Although monogamy (having sex with only one partner) will not keep you from becoming infected with HPV if either of you has ever had sex with someone who was infected, limiting your number of sex partners will reduce your risk of infection.
Completely avoiding contact of the areas of your body that can become infected with genital human papilloma virus (HPV) (like the mouth, anus, and genitals) with those of another person may be the only way to keep from becoming infected with HPV. This means not having vaginal, oral, or anal sex, but it also means not allowing those areas to come in contact with someone else’s skin.
HPV vaccines can prevent infection with the types of HPV most likely to cause cancer and genital warts. See HPV Vaccines for more on this.
Having few sex partners and avoiding sex with people who have had many other sex partners helps lower the risk of exposure to genital HPV.
Condoms can help protect you from genital HPV infection, but HPV might be on skin that’s not covered by the condom. And condoms must be used every time, from start to finish. The virus can spread during direct skin-to-skin contact before the condom is put on, and male condoms don’t protect the entire genital area, especially for women. The female condom covers more of the vulva in women, but hasn’t been studied as carefully for its ability to protect against HPV. Condoms are very helpful, though, in protecting against other infections that can be spread through sexual activity.
It’s usually not possible to know who has genital HPV infection, and HPV is so common that even using these measures doesn’t guarantee that a person won’t get the virus. But they can help reduce the number of times a person is exposed to HPV.
Using condoms may reduce the risk of spreading HPV, but only the skin that is covered by or comes in contact with the condom is protected from HPV. The virus can infect any uncovered skin on the genitals, groin, thighs, anus, and rectum and possibly in the mouth.
The U.S. Food and Drug Administration (FDA) has approved three vaccines that protect against HPV.
Gardasil® protects against HPV types 6, 11, 16 and 18. (Types 16 and 18 cause 70% of cervical cancers, while types 6 and 11 cause about 90% of genital warts.)
Gardasil 9 protects against the same HPV types as Gardasil plus 5 additional types that cause about 15% of cervical cancers.
Ceravix® protects against HPV types 16 and 18.
All three vaccines are approved for use in girls and women 9 to 26 years of age, and the two Gardasil vaccines are approved for the prevention of genital warts in boys and men 9 through 26 years of age. The vaccines are given in 3 doses over a period of 6 months. The same vaccine should be used each time a dose is administered.
The American Academy of Pediatrics (AAP) recommends that both girls and boys receive the HPV vaccine series when they are 11 to 12 years old. The vaccine is also recommended for men up to 21 and women up to 26 years of age who did not receive it when they were younger.
The FDA says the vaccines are considered safe but are only effective if given before an initial exposure to the virus. AAP recommends that young people who are sexually active still receive the vaccination, as those already infected with one type of HPV infection may benefit from the protection against other types included in the vaccine.
How can HPV be prevented?Are men screened for HPV infection?
Men are not routinely screened for HPV infection unless they fall into a category at high risk for cancer, such as those with compromised immune systems or men who have sex with men. Currently, there are no tests approved by the Food and Drug Administration (FDA) to detect HPV in males; however, some specialty labs have validated DNA tests for analyzing anal swabs from males. As in cervical samples, positive results will need to be followed up by the healthcare provider with further testing, including a more thorough exam and possible biopsy.
​I'm a woman who has had the HPV vaccine. Do I need cervical cancer screening?​​​​
Yes. Because currently available HPV vaccines do not protect against all cervical cancers, women who have been vaccinated still need routine screening.
How common is HPV? Who gets it?
HPV infections are so common that nearly all men and women will get at least one type of HPV at some point in their lives. Most people never know that they have been infected and may give HPV to a sex partner without knowing it. About 79 million Americans are currently infected with some type of HPV. About 14 million people in the United States become newly infected each year.
Genital human papilloma virus (HPV) is a very common virus. Some doctors think it’s almost as common as the cold virus. The Centers for Disease Control (CDC) estimate that about 14 million people get a new HPV infection every year in the US.
Nearly all men and women who have ever had sex get at least one type of genital HPV at some time in their lives. This is true even for people who only have sex with one person in their lifetime.
What kinds of problems does HPV infection cause?
Most people with HPV never develop symptoms or health problems. Most HPV infections (9 out of 10) go away by themselves within two years. But, sometimes, HPV infections will last longer, and can cause certain cancers and other diseases. HPV infections can cause:
cancers of the cervix, vagina, and vulva in women;
cancers of the penis in men; and
cancers of the anus and back of the throat, including the base of the tongue and tonsils (oropharynx), in both women and men. Every year in the United States, HPV causes 30,700 cancers in men and women.
How do people get an HPV infection?
People get HPV from another person during intimate sexual contact. Most of the time, people get HPV from having vaginal and/or anal sex. Men and women can also get HPV from having oral sex or other sex play. A person can get HPV even if their partner doesn’t have any signs or symptoms of HPV infection. A person can have HPV even if years have passed since he or she had sexual contact with an infected person. Most people do not realize they are infected. They also don’t know that they may be passing HPV to their sex partner(s). It is possible for someone to get more than one type of HPV.
It's not very common, but sometimes a pregnant woman with HPV can pass it to her baby during delivery. The child might develop recurrent respiratory papillomatosis (RRP), a rare but dangerous condition where warts caused by HPV (similar to genital warts) grow inside the throat.
There haven’t been any documented cases of people getting HPV from surfaces in the environment, such as toilet seats. However, someone could be exposed to HPV from objects (toys) shared during sexual activity if the object has been used by an infected person.
Genital human papilloma virus (HPV) is spread mainly by direct skin-to-skin contact during vaginal, oral, or anal sex. It’s not spread through blood or body fluids.
The virus often spreads from one person to another very soon after a person starts having sex. It can be spread by genital contact without sex, but this is not common. Oral-genital and hand-genital spread of some genital HPV types has been reported. And there may be other ways to become infected with HPV that aren’t yet clear. For instance, it might be spread through deep kissing or shared sex toys.
Transmission from mother to newborn during delivery is rare, but it can happen, too. When it does, it can cause warts (papillomas) in the infant’s breathing tubes (trachea and bronchi) and lungs, which is called respiratory papillomatosis. These papillomas can also grow in the voice box, which is called laryngeal papillomatosis. Both of these infections can cause life-long problems.
You DO NOT get genital HPV from:
Toilet seats
Hugging or holding hands
Swimming in pools or hot tubs
Family history (heredity)
Sharing food or utensils
Being unclean
Who should get HPV vaccine?
All girls and boys who are 11 or 12 years old should get the recommended series of HPV vaccine. The vaccination series can be started at age 9 years. Teen boys and girls who did not get vaccinated when they were younger should get it now. HPV vaccine is recommended for young women through age 26, and young men through age 21. HPV vaccine is also recommended for the following people, if they did not get vaccinated when they were younger:
young men who have sex with men, including young men who identify as gay or bisexual or who intend to have sex with men through age 26;
young adults who are transgender through age 26; and
young adults with certain immunocompromising conditions (including HIV) through age 26.
Why are two doses recommended for 9–14 year olds, while older adolescents need three doses?
Since 2006, HPV vaccines have been recommended in a three-dose series given over six months. In 2016, CDC changed the recommendation to two doses for persons starting the series before their 15th birthday. The second dose of HPV vaccine should be given six to twelve months after the first dose. Adolescents who receive their two doses less than five months apart will require a third dose of HPV vaccine.
Teens and young adults who start the series at ages 15 through 26 years still need three doses of HPV vaccine Also, three doses are still recommended for people with certain immunocompromising conditions aged 9 through 26 years.
CDC makes recommendations based on the best available scientific evidence. Studies have shown that two doses of HPV vaccine given at least six months apart to adolescents at age 9–14 years worked as well or better than three doses given to older adolescents and young adults. Studies have not been done to show this for adolescents starting the series at age 15 years or older.
Why is HPV vaccine recommended at age 11 or 12 years?
For HPV vaccine to be most effective, the series should be given prior to exposure to HPV. There is no reason to wait to vaccinate until teens reach puberty or start having sex. Preteens should receive all recommended doses of the HPV vaccine series long before they begin any type of sexual activity.
How well does HPV vaccine work?
HPV vaccines work extremely well. Clinical trials showed HPV vaccines provide close to 100% protection against cervical precancers and genital warts. Since the first HPV vaccine was recommended in 2006, there has been a 64% reduction in vaccine-type HPV infections among teen girls in the United States. Studies have shown that fewer teens are getting genital warts and cervical precancers are decreasing. In other countries, such as Australia, where HPV vaccination coverage is higher than in the United States, large decreases have been observed in these HPV-associated outcomes. HPV vaccines offer long-lasting protection against HPV infection and HPV disease. There has been no evidence to suggest that HPV vaccine loses any ability to provide protection over time. Data are available for about 10 years of follow-up after vaccination.
Like all vaccines, HPV vaccine is monitored on an ongoing basis to make sure it remains safe and effective. If it turns out that protection from HPV vaccine is not long-lasting, then the Advisory Committee on Immunization Practices would review the data and determine whether a booster dose would be recommended.
Even if it has been months or years since the last shot, the HPV vaccine series should be completed—but they do not need to restart the series.
HPV vaccine is recommended based on age, not sexual experience. Even if someone has already had sex, they should still get HPV vaccine. Even though a person’s first HPV infection usually happens during one of the first few sexual experiences, a person might not be exposed to all of the HPV types that are covered by HPV vaccines.
Role of HPV Testing and HPV Typing in Cervical Cancer Prevention and Detection​​​​​​​
Nearly 50 percent of lesions missed by a single Pap test cytology screen may be detected by additional testing for oncogenic Human Papillomavirus (HPV) infection. HPV testing for carcinogenic HPV types is commonly used in the United States to triage equivocal Pap test diagnoses for referral for further examination by colposcopy. HPV testing is also widely accepted as a co-test for primary screening of women over 30, since women without carcinogenic HPV infection are at extremely low risk for clinically relevant cervical disease for many years.
In addition, recent studies suggest that HPV testing alone may be a reasonable alternative to Pap smear alone for cervical cancer screening. HPV-based screening seems to promote earlier identification of women at high risk of cervical cancer and, in one recently presented study, safely extended three-year screening intervals for this population. It remains unclear at this time what combination of HPV testing, Pap smear, or co-testing with HPV and Pap represents the optimal screening strategy. The Society of Gynecologic Oncology (SGO) encourages additional study of this issue and remains part of the team of cancer care professionals vested in establishing appropriate screening guidelines.
HPV typing for the most common types of the disease, HPV 16 and HPV 18, is also available for clinical use. SGO believes that HPV testing and typing should be viewed as important, additional diagnostic and screening tools, however:
These tests should not replace other cervical cancer screening methods, including regular Pap tests and gynecologic examinations. This recommendation may change, depending on current clinical practices and the enhancement of guidelines for the use of both HPV testing and HPV typing.
HPV testing and HPV typing should not be used as a prescreening tool for HPV vaccination. It is SGO’s position that, because positive or negative oncogenic HPV testing or HPV 16/18 typing is not helpful in determining those who would clinically benefit from HPV vaccination and would add unnecessary additional costs, identifying the presence of HPV infection should not be used as a prescreening tool for HPV vaccination.
Low-risk genital HPV types
HPV types that tend to cause warts and not cancer are called low-risk types. Low-risk genital HPV infection can cause cauliflower-shaped warts on or around the genitals and anus of both men and women. In women, warts may appear in areas that aren’t always noticed, such as the cervix and vagina.
High-risk genital HPV types
HPV types that tend to cause cancer are called high-risk types. These types have been linked to cancers in both men and women. Doctors worry about the cell changes and pre-cancers these types cause because they are more likely to grow into cancers over time.
What are the risk factors for genital HPV for women ?
Having many sex partners
Having a partner who has had many partners
Being younger than 25 years of age
Starting to have sex at an early age (16 years or younger)
Having a male partner who’s not circumcised (hasn’t had the foreskin of the penis removed). Men who still have their foreskins are more likely to get and stay infected with human papilloma virus (HPV) and pass it on to their partners. The reasons for this are unclear.
What are the symptoms of HPV?
Genital human papilloma virus (HPV) infection usually has no symptoms, unless it’s an HPV type that causes genital warts. Genital warts may appear within weeks or months after contact with a partner who has HPV. The warts may also show up years after exposure, but this is rare. The warts usually look like small bumps or groups of bumps in the genital area. They can be small or large, raised or flat, or shaped like a cauliflower. If they’re not treated, genital warts might go away, stay and not change, or increase in size or number. But warts rarely turn into cancer.
Most people will never know they have HPV because they have no symptoms. In most people, their immune system attacks the virus and clears the HPV infection within 2 years. This is true of both high-risk and low-risk HPV types. But sometimes HPV infections are not cleared. This can lead to cell changes that over many years may develop into cancer.
Can HPV be treated?​​​​​​​
There’s no treatment for the virus itself. But most genital human papilloma virus (HPV) infections go away with the help of a person’s immune system.
Even though HPV itself cannot be treated, the cell changes caused by an HPV infection can. For example, genital warts can be treated. Pre-cancer cell changes caused by HPV can be found by Pap tests and treated. And head and neck, cervical, anal, and genital cancers can be treated, too.
What’s the difference between a Pap test and an HPV test?​​​​​​​
A Pap test is used to find cell changes or abnormal cells in the cervix. (These abnormal cells may be pre-cancer or cancer, but they may also be other things, too.) Cells are lightly scraped or brushed off the cervix. They are sent to a lab and looked at under a microscope to see if the cells are normal or if changes can be seen. The Pap test is a very good test for finding cancer cells and cells that might become cancer.
Human papilloma virus (HPV) is a virus that can cause cervix cell changes. The HPV test checks for the virus, not cell changes. The test can be done at the same time as the Pap test, with the same swab or a second swab. You won’t notice a difference in your exam if you have both tests. A Pap test plus an HPV test (called co-testing) is the preferred way to find early cervical cancers or pre-cancers in women 30 and older.
If you are a woman under age 30​​​​​​​
The American Cancer Society recommends that women between ages 21 and 29 should have a Pap test every 3 years (at ages 21, 24, and 27) to test for cervical cancer and pre-cancers. These women should not get the HPV test with the Pap test (co-testing) because HPV is so common in women these ages that it’s not helpful to test for it. But HPV testing may be used in this age group after an abnormal Pap test result.
The most common abnormal Pap test result seen is called ASC-US (your health care provider may say this as “ask us”). ASC-US cells usually are not pre-cancer, but they aren’t quite normal either. If there are ASC-US cells in your Pap test result, an HPV test may be done to see if HPV is causing the cell changes. If HPV is found, you’ll need more tests.
In cases like this, the HPV test is used to help decide if more testing is needed. This is not the same as using the HPV test with the Pap test as part of your normal health visit.
Women who are HIV positive or who have been diagnosed or treated for a cervical cancer or pre-cancer should talk to their health care providers about how often they should be tested for cervical cancer and what tests should be used.
If you are a woman aged 30 to 65
The American Cancer Society recommends that women aged 30 to 65 have an HPV test with their Pap test (co-testing) every 5 years to test for cervical cancer. Talk to your health care provider about co- testing. It’s also OK to continue just to have Pap tests every 3 years.
Women who are HIV positive or who have been diagnosed or treated for a cervical cancer or pre-cancer should talk to their health care providers about how often they should be tested for cervical cancer and what tests should be used.
Why should women over age 30 with normal test results change to co-testing every 5 years and start doing HPV testing? Is that safe?​​​​​​​
Cell changes in the cervix happen very slowly. It usually takes more than 10 years for cell changes to become cancer. Pap tests have been done yearly in the past, but now we know that Pap tests are not needed every year – every 3 years is enough. In fact, doing Pap tests every year can lead to unneeded treatment of cell changes that would never go on to cause cancer.
One of the benefits of adding testing for HPV is that women can get cervical cancer testing even less often. Getting the Pap test and HPV test (co-testing) every 5 years means fewer tests, follow-up visits, and treatments may be needed. Women with normal Pap and HPV test results have almost no chance of getting cervical cancer within at least 5 years.
Co-testing is preferred, but it’s also OK to continue to have the Pap test alone every 3 years.
What about testing other sites on the body, or testing men?​​​​​​​
There’s no FDA-approved HPV test for men at this time, nor is there an FDA-approved HPV test to find the virus anywhere besides the cervix, including the mouth or throat.
The FDA has only approved tests to find HPV in a woman’s cervix, where positive results can be managed with extra testing and prompt treatment if the infection causes abnormal cell growth. Although HPV tests might be used in research studies to look for HPV in other sites, there’s no proven way to manage positive findings. Also, the accuracy of the test itself may be affected by the site it’s taken from and the way the sample is taken.
Finally, there’s no useful test to find out a person’s “HPV status,” because an HPV test result can change over a period of months or years as the body fights the virus. (See “If I have a positive HPV test, what does it mean?”)
If I have a positive HPV test, what does it mean?​​​​​​​
If you have cervical human papilloma virus (HPV) infection and an abnormal Pap test result, your health care provider will explain what other tests you might need.
If you have cervical HPV infection and a normal Pap test result, it means that you have genital HPV, but no cell changes were seen on your Pap test. There are 2 options:
You’ll most likely be tested with an HPV test and a Pap test again in 12 months.
In most cases, re-testing in 12 months shows no sign of the virus.
If the virus does go away and your Pap test is normal you can go back to normal screening.
If the virus is still there or changes are seen on the Pap test, you’ll need more testing.
As another option, the provider may suggest testing specifically for HPV-16 or both -16 and -18 (the 2 types that are most likely to cause cervical cancer).
If testing shows that you have HPV-16 and/or -18, more testing will be needed.
If the test doesn’t show infection with HPV-16 and/or -18, you should be retested in 12 months with both an HPV test and a Pap test.
If HPV goes away, can you get it again?
There are many types of HPV. You may have one type that goes away, but you can get another different type. It’s possible to get the same type again, but the risk of this is low.
Will HPV affect my pregnancy or my baby?​​​​​​​
HPV infection does not directly affect the chances of getting pregnant.
If HPV infection leads to cervical changes that need to be treated, the treatment should not affect your chances of getting pregnant. But if you have many treatments and biopsies, which can happen with more frequent screening, the risk of pre-term labor and low birth weight babies can go up.
HPV is rarely passed from a mother to her baby. The rare cases where this has happened do not involve the types of HPV that can cause cancer. “How do you get genital HPV?” has more on how HPV is transmitted from mother to baby during pregnancy.
​​​​​​​How often do you need to get an HPV test?
Your first HPV test
If you are 30 or older and have not had an HPV test, tell your doctor or nurse that you want to be tested for HPV test along with your next Pap. If you are not sure whether you have already had the HPV test, ask! If you are between the ages of 20 and 30, HPV testing should only be used when your Pap result is inconclusive (also called an "ASC-US" Pap). That’s because the infection is very common in younger women, but almost always temporary and harmless. (Note that the most recent guidelines do not recommend HPV testing at all for girls under 20.)
​​​​​​​Repeat HPV tests
If you are over 30, how often you need to repeat the HPV test depends on your past results. For example, if both your Pap and HPV test results are normal, re-testing is needed just once every three years.

​​​​​​​

​​​​​​​

​​​​​​​