You probably know about the human papilloma virus (HPV) that causes warts on your hands and feet. Many of us have had at least one wart that resulted in a visit to the pharmacy or the doctor’s office for treatment. What you may not know is that many different types of HPV exist. Some are harmless, some cause warts, and others are linked to certain types of cancer.
We know about more than 100 types of HPV. This virus causes infection in the skin and mucous membranes like the moist inner lining of the mouth. Warts are a common skin problem. Some types of HPV cause warts on the hands (common warts). Others affect the bottom of the feet (plantar warts). Less common types of HPV produce warts in the mouth, throat and larynx (voice box).
At least 40 types of HPV can infect the genitals (sex organs). These types, also called HPV strains, can be grouped into either low or high risk HPV. Low risk strains are less likely to cause cancer. We know that low risk HPV causes infections in the skin and mucous membranes of the genital area. This includes the inner lining of the vagina (birth canal) and the anus. These viruses usually cause warts on the penis, the vulva (external genital organs of the woman), and around the anus. All genital warts are caused by low risk HPV.
Almost all cancer of the cervix (the lower part of the uterus) can be traced back to specific strains of oncogenic (cancer causing) HPV. These strains are high risk as they are strongly linked to cancer of the cervix. In fact, research shows that almost all cervical cancers are caused by high risk HPV.
You can get HPV from skin-to-skin contact with another person who has it. Some HPV can survive on warm moist surfaces, such as locker and gym changing rooms. Genital strains of HPV are transferred in different types of sexual contact, including sexual touching and sexual intercourse.
After you have been exposed to HPV, it can take many months for signs of infection to appear. Often, the first sign is a wart. If you see a bump or cluster of bumps on your skin or in the genital area, it could be a wart. A wart usually has a bumpy or irregular surface and sometimes there are dark spots or ‘seeds’ in it. Talk with your doctor about any unusual lumps you notice. Your doctor can usually diagnose a wart by examining you.
Women may find out about HPV after a Pap test. This test is an important screening test for cervical cancer. It involves the doctor gently collecting cells from the cervix to be sent to the lab for testing. If the cells are infected with HPV, your Pap test can be abnormal.
If you have warts on your skin or in the genital area, your doctor may suggest liquid nitrogen treatment. This liquid freezes the warts and is applied weekly until the warts are gone.
Aldara® is a cream that activates your immune (defence) system. It is used to treat genital warts. Aldara® is usually applied at home three times a week, for up to 12 weeks. Your doctor may recommend other treatments.
If you are a young woman with an abnormal Pap test due to HPV, you will often get better without treatment. An abnormal result is classed as either low grade (minor), or high grade (more serious). If the Pap test shows low grade changes in the cells of the cervix, your doctor may ask you to be tested more often for the next two years. This makes sure the cells return to normal. We know that your immune system can often clear low risk HPV from your body within a year or two.
If the Pap test shows high grade cell changes, or if you have a second Pap test with abnormal cells, you will likely be referred for further testing. A colposcopy is a special test that allows a gynecologist to look closely at abnormal cells on the cervix. The gynecologist may recommend a biopsy of these cells or special treatment to remove them. This treatment is highly effective and almost always results in a complete cure.
Every province has its own guidelines for women with abnormal Pap tests. Your doctor will be able to tell you about screening programs and treatment options in your province.
This new kind of testing is available in some provinces. It can be used to see what strain of HPV is present in the cells from the cervix. If your Pap test is abnormal, an HPV DNA test may tell whether cells from your cervix are infected with a low or high risk HPV strain.
Currently, HPV DNA testing is not widely available. However, it is likely to become an important part of cervical cancer screening programs over the next few years.
To avoid HPV that causes warts on your hands and feet, avoid skin-to-skin contact with those who have warts. Do not share razors, towels, socks and shoes. The virus can live on warm moist surfaces, so try not to walk barefoot in public showers and changing rooms.
HPV is the most common STI (sexually transmitted infection) in Canada and in the world. By using condoms every time you have sex, you can reduce your risk of infection by up to 70 per cent.
A new HPV vaccine called Gardasil® has been available in Canada since July 2006. It protects against four strains - HPV 6, 11, 16 and 18. This may not seem like a lot when 40 strains of genital HPV are out there. However, low risk HPV strains 6 and 11 cause 95 per cent of all genital warts. The high risk HPV strains 16 and 18 cause over 70 per cent of all cancers of the cervix.
The HPV vaccine is very effective. Gardasil® was tested in four clinical trials over several years. Close to 10,000 women between 16 and 26 years of age received three doses of Gardasil®. Results were compared to a similar group who did not receive it. These studies showed that Gardasil® prevented genital warts in 99 to 100 per cent of women in the study group. Gardasil® also prevented 99 to 100 per cent of pre-cancer changes in the cervix caused by HPV 16 and 18.
Some new studies on HPV show that the vaccine protects against other cancer causing HPV strains not in the vaccine. This is called cross protection. More information will emerge about this in the next few years.
In Canada, the vaccine has been approved for girls from nine to 26 years of age. The ideal time for girls to get immunized is before they become sexually active. The Canadian Pediatric Society and the National Advisory Committee on Immunization in Canada (NACI) both recommend the vaccine for all girls of these ages. The Canadian Pediatric Society also recommends that all girls from nine to 13 years be routinely immunized.
Over the past year, HPV vaccine has been introduced into school immunization programs in some provinces. You may have the option of having your daughter immunized in this setting.
Even if a woman is sexually active and has had genital warts or an abnormal Pap test, the vaccine is still recommended. Remember it protects against four strains of HPV, though she may have been exposed to just one.
Even women over age 26 may want to consider the vaccine. Discuss your situation with your doctor. Some countries have approved the vaccine for men, but in Canada it is only currently recommended for women. For older girls and women, it is important to check if you have any third party insurance through work or school. Many insurance plans will pay for at least some of the vaccine cost.
Gardasil® is given in three doses over six months. The recommended immunization schedule is to have an initial dose, then repeat it at two months and six months. This vaccine is considered safe and well tolerated. The most common side effects are pain, swelling and redness at the injection site. Other side effects such as fever are extremely rare.
National Advisory Committee on Immunization statement on Gardasil (on the Canadian Cancer Society website) www.cancer.ca
Canadian Paediatric Society, Immunization – HPV Vaccine, information from Canada’s paediatric experts
The Society of Obstetricians and Gynaecologists of Canada information website for teens, adults, parents and health professionals
We know the vaccine works very well for at least five years. It may last much longer than that. More information on whether a booster is needed will become clear as research studies continue over the next few years.
Understanding HPV is only the first step in protecting from infection. Getting regular Pap tests is an important part of your health care even if you are immunized against HPV. The vaccine can prevent more than 70 per cent of cervical cancer. However, other strains of HPV are not in the vaccine. Talk with your doctor about whether you should have a Pap test, and whether HPV immunization is the right choice for you and your family.