Human papillomavirus (HPV)

Human papillomavirus (HPV) is the most common viral sexually transmitted infection (STI). Around 85 per cent of people who have ever been sexually active will get HPV at some stage of their life. 

On this page

• Genital warts
• HPV and cancer
• HPV vaccination 

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There are over 100 types of HPV affecting various parts of the body. Over 40 of these types affect the genital area, and just a few will affect the cells inside the cervix. Most people who acquire the virus will never be affected by it at all. The vast majority of HPV infections clear on their own, which can take months or years, but they do eventually go away. In five per cent of cases the virus will persist but again, it can be months or years before the virus will cause any other problems (if at all). Women will usually learn that they have the virus because they have abnormal findings on their cervical screening test. 

In most cases, people with an HPV infection don't even know that they have it. Even the most dangerous infections can go unnoticed by the person carrying it. Because people don't know they have it and because HPV is highly infectious, it can easily be passed on during unprotected sex. Younger people are more likely to pass the virus around because they tend to change sexual partners more often.  

HPV infections are divided into high-risk or low-risk types. High-risk infections can lead to abnormal cell changes in the cervix and, in some cases, cervical cancer. Some low-risk infections can cause genital warts but will not lead to cervical cancer. 

The Gardasil injection, which adolescent girls are offered in early high school in Australia, protects against two of the most common high-risk and two of the most common low-risk HPV infections, and aims to reduce cervical cancer and genital warts in the community. 

Genital warts

Only some low-risk HPV infections will lead to genital warts. About 85 per cent of people acquire HPV as a result of having sex, whereas only 10 per cent will develop warts (if they have not been vaccinated). Genital warts are little warty lumps, usually found on the external genital region, around the vagina, anus and, in men, on the penis. Condom and dental dam use will give you some protection against warts but not always. This is because warts can be spread by skin-to-skin contact and the skin affected is not always limited to the immediate genital area. Warts can develop around three months after exposure to the virus and, in some cases, they may actually clear by themselves. You may or may not know that you were exposed to the virus because your sexual partner may not have had obvious signs. Your partner does not have to have genital warts for you to develop them.

Genital warts can be treated by freezing, burning, laser treatment, or using a special cream (called Aldara), which works by boosting the immune system, but the warts often come back.  Do not use wart paint that you use on other parts of your body on genital warts. 

HPV and cancer

For a small number of women (5 to 10 per cent) certain types of HPV can become persistent, resulting in changes in the cells in their cervix. Generally it is this persistent infection with high-risk HPVs that leads to cervical cancer.

Smoking may lower a woman's immune system and therefore increase her chances of developing abnormalities. Other factors that may affect a woman’s immunity include active hepatitis B and C, HIV/AIDS, recent glandular fever and immunosuppressive drugs.

HPV vaccination 

Adolescent girls and boys often refer to the HPV vaccine as ‘the cancer needle’.  There is a government-funded school vaccination program (for 12- and 13-year-old girls and boys) to prevent the development of some HPVs. Prevention will be most effective if you have the vaccine before the first time that you have sex. 

Two HPV vaccines are licensed for use in Australia: Gardasil and Cervarix. The one used in Australian schools is called Gardasil and it makes your body form antibodies to HPV 16 and 18 (which cause 70 per cent of cervical cancer), and 6 and 11 (which produce 90 per cent of genital warts). It can prevent the majority of cases of cervical cancer and genital warts if given early. Cervarix also helps the body to make antibodies to HPV 16 and 18 and can therefore prevent around 70 per cent of cervical cancer, but will not protect you against genital warts.

There is new evidence to show that the vaccines are useful even if you have been sexually active in the past, and even if you have had cervical screening tests before that have shown cell changes (around 66 per cent effective). The vaccines, however, are preventative and do not treat abnormalities; neither can they eradicate a current HPV infection. Women 45 years and under are eligible to be vaccinated. It is still useful to get vaccinated if you are in a monogamous relationship (currently only have one sexual partner) or are in a same-sex relationship.

If you missed out on vaccination through the school system, you can get the vaccine through your GP. It costs around $150 per injection, and you will need three injections over six months. While this is expensive, it is a very good investment in your health. If you have only received one or two doses and there has been some delay in receiving the second or third dose, you don’t need to start the vaccination course again: just finish the course. You will still need to have cervical screening tests and follow-up with your GP.

If, after you have been vaccinated, a cervical screening test shows abnormal changes to your cervix this does not mean the vaccine has failed. Changes to your cervix may be caused by HPV types that are not covered by the vaccine or you may have been infected before you had the vaccine. Even though it is expected that cervical changes will continue to be common, it is hoped that the rate of cervical cancer will reduce dramatically as a result of this vaccination.

The side effects of the vaccine include mild pain and redness at the injection site. The vaccine is safe. Allergic reactions are exceedingly rare. 

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