Human papillomavirus (HPV)
Human papillomavirus (HPV) is one of the most common sexually transmitted infections (STIs) in Canada and worldwide. Many types of HPV have been identified, with some leading to cancer and others to skin lesions such as anogenital warts.
In Canada, two vaccines are available to help prevent some types of HPV, including the ones that cause 70% of cervical cancers and 70-90% of anogenital warts.
The various types of HPV can lead to different health outcomes. Some types can infect areas such as the hands and feet, while other types target the anogenital area and are transmitted during vaginal, oral, or anal sex, or during intimate skin-to-skin contact with someone who is infected. It is possible to be infected by more than one type of HPV at a time.
It is estimated that as many as 75% of sexually active men and women will have at least one anogenital HPV infection in their lifetime, but most people with healthy immune systems will eventually clear the infection from their bodies. Of those infected, only a small proportion will go on to develop cancer.
There is no cure for HPV infections, but many of the symptoms are treatable. Practicing safer sex reduces your chances of getting an HPV infection or another STI. There is no precise way to determine in which people HPV infections will persist and lead to cancer, but for women, routine Pap (Papanicolaou) testing is an important screening tool for cervical cancer and allows early stage treatment with complete cure. There is no equivalent of Pap testing in males. Penile cancer is rare and occurs in less than 1% of all male cancers. Anogenital warts are more frequent.
Symptoms of HPV
Many people who have HPV have no symptoms of the infection. Anogenital warts (also called Condylomata) are one sign of HPV infection. They may look like a small cauliflower or may be flat. Many people with HPV will have no obvious signs of infection because the warts may be inside the body or if on the skin, too small to be seen.
In women, warts may appear on the vulva, thigh, anus, rectum, or in the vagina or urethra with the cervix being a common HPV infection site. During pregnancy, the number and size of warts can increase, but usually decrease after delivery. With an inactive infection, the cells of the cervix appear normal under a microscope during a Pap test and the woman may never know she was infected. With an active infection, the cervical cells undergo a change. An active infection can follow one of two courses:
- The abnormal cells become normal again and the infection is inactive or cleared from your body by your immune system. However, it is possible that an inactive infection can become active again, for reasons that aren't clearly understood.
- The abnormal cells slowly progress to cervical cancer.
In men, the warts may appear on the penis, scrotum, thigh, anus, rectum, or in the urethra.
HPV DNA testing is available in Canada but access varies across the country and is not part of a woman's regular check-up or Pap test. If not covered by your provincial and territorial health programs, you may have to pay for HPV testing. However, where recommended and available, Pap tests are currently used to decide if a woman is at risk of developing pre-cancerous and cancerous changes in the cervix thereby allowing these changes to be treated or closely followed and reduce the chances of developing cancer.
In men, HPV testing is currently under study but once the malignant lesion has developed, treatment choices include complete surgical removal of the cancerous tissue, chemotherapy and radiation therapy.
The health risks of HPV
HPV causes almost all cervical cancers but is also linked to cancer of the throat, oral cavity, penis, anus, vagina or vulva. More research is needed to define the extent of these linkages.
Anogenital warts, although rarely associated with cancer, are still a significant burden for those affected often leading to physical, emotional and social problems. They can be effectively treated by applying prescribed medication either in a doctor's office or by you at home. Other medical treatments include cryotherapy (freezing), an electric current, or a laser or surgical removal of the warts but these methods do not always eliminate HPV infection. Even with treatment, warts can recur.
HPV does not appear to affect a woman's ability to become pregnant. Although considered rare, the baby may be at risk of getting an HPV infection in the throat. A C-section delivery is not routinely recommended, unless there is a significant obstruction or other risks.
Protecting against HPV through immunization
Health Canada has authorized two vaccines to prevent infections from the most common types of HPV, Gardasil™ (for females and males) and Cervarix™ (for females only). Both vaccines appear to be safe and very effective in preventing HPV infection and changes in the cells of the cervix related to these types of HPV.
Studies have found both Gardasil™ and Cervarix™ to be safe. Other than a brief soreness at the injection site, participants reported few side effects. The vaccines cannot cause disease because they contain no live biologicals or DNA and are thus not infectious. Also, the vaccines do not contain any preservative or antibiotics, including thimerosal or mercury. It is important to note that Cervarix™ contains a special new adjuvant/additive (ASO4) which studies have also shown to be safe.
If you are infected with one type of HPV you can still benefit from the HPV vaccine. It can protect you against other strains of the virus. Unfortunately, even if you are vaccinated, you are still at risk for some types of HPV not covered by the vaccine. It is important that women who receive the vaccine still have regular Pap tests and practice safer sex.
Neither vaccine has an impact on an existing infection or any consequences of infection (e.g. anogenital warts and cancerous or pre-cancerous changes) that you may already have. Talk to your doctor for more information.
A vaccine called Gardasil®, which prevents certain types of HPV, has been approved for use in Canada. The vaccine protects against infection with two high risk types of HPV (16 and 18) which cause approximately 70% of cervical cancers and two low risk types of HPV (6 and 11) which cause approximately 90% of anogenital warts.
The vaccine has been approved for use in females ages nine to 45 and in males ages nine to 26, and involves one dose given initially followed by one dose two months later and another dose given six months after the first dose was given. Pregnant and lactating women should avoid the vaccine. Talk to your doctor for more information.
In males, studies have demonstrated efficacy in preventing external lesions due to types 6 and 11. Failure to demonstrate the same efficacy in preventing penile and ano-rectal cancer was likely due to the rarity of these lesions.
Recent studies indicate good protection against HPV types in the vaccine for five years of follow-up. Studies are ongoing to determine if further immunization is needed for vaccinated women and men to have continued protection.
A vaccine, called Cervarix™, which prevents certain types of HPV, has been approved for use in Canada. The vaccine protects against infection with two high risk types of HPV (16 and 18) which cause approximately 70% of cervical cancers.
The vaccine has been approved for use in females ages nine to 25, and involves one dose given initially followed by one dose a month later and another dose given six months after the first dose was given. Pregnant and lactating women should avoid the vaccine. Talk to your doctor for more information.
Recent studies indicate good protection against HPV types in the vaccine for six years of follow-up. Studies are ongoing to determine if further immunization is needed for vaccinated women to have continued protection. Studies are also currently being done in males.
National Advisory Committee on Immunization (NACI) recommendations
In February 2007, based on sound scientific consideration, the National Advisory Committee on Immunization (NACI) issued recommendations for the use of Gardasil® for females ages nine to 26. In January 2012, NACI issued an update on human papillomavirus vaccines, which included recommendations in light of the expanded use of Gardasil® for males ages nine to 26 and females ages 27 to 45, as well as the approval of Cervarix™ for females.
Currently, HPV vaccine Cervarix™ or Gardasil® is recommended by NACI for:
- females between nine and 13 years of age, before the onset of sexual intercourse
- females between the ages of 14 and 26 years of age, even if they are already sexually active, have had previous pap abnormalities, or have had a previous HPV infection
- females over 26 years of age, even if they are already sexually active, have had previous pap abnormalities, or have had a previous HPV infection
Currently, HPV vaccine Gardasil® is recommended by NACI for:
- males between 9 and 13 years of age, before the onset of sexual intercourse
- males between the ages of 14 and 26 years of age, even if they are already sexually active or have had a previous HPV infection
- males who have sex with males (MSM) who are 9 years of age and older
Use of HPV vaccine Cervarix™ is not currently recommended by NACI for:
- females under nine years of age
- pregnant women
Use of HPV vaccine Gardasil® is not currently recommended by NACI for:
- females under nine years of age
- pregnant women
Minimizing your risk
These measures can help protect you against HPV and its consequences.
- Anyone who has had sex is at risk for HPV. Since not all infections have symptoms or noticeable symptoms, you often cannot tell if you are infected.
- If you are a woman, see your doctor regularly for a Pap test and/or a HPV DNA test, where recommended and available - even if you have been vaccinated for HPV.
- Learn about STIs, including their signs, symptoms, consequences, and methods of transmission.
- Learn about safer sex methods and use them consistently.
- Make informed decisions about your sexual health. Talk to your partner(s) about their STI status and the use of protection. Remember that the previous sexual behaviours of your partner are also a risk for you, especially if they have had multiple partners.
- Correctly and consistently using a condom during sex may reduce your risk of getting HPV, as well as preventing other STIs. However, remember that the areas of skin not covered by the condom are not protected.
- If you are a female between nine and 45 years of age, consider immunization with the HPV vaccine.
- If you are a male between nine and 26 years of age, consider immunization with the HPV vaccine.
- If you are a male who has sex with men and are nine years of age or older, consider immunization with the HPV vaccine.
- If you are sexually active, talk to your doctor about HPV and other STIs you may have been exposed to.
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