Human papillomavirus (HPV)

Human papillomavirus (HPV) is a group of more than 100 different types of viruses. More than 40 types of HPV are transmitted through sexual intercourse, genital skin-to-skin contact and oral sex. These types can infect the genital areas of both men and women, including the penis, anus, vulva, vagina and cervix, as well as the oral cavity and throat (the oropharynx).

Sexually transmitted HPV are either high-risk or low-risk:

• High-risk HPV
  Infection with high-risk HPV can cause the cells in a woman’s cervix to change or become abnormal. These pre-cancerous changes can lead to cervical cancer. HPV 16 and 18 are the most common high-risk types and are responsible for 70% of cervical cancers.
  
  Infection with high-risk HPV, especially HPV 16, is also linked to cancers of the penis, anus, vulva, vagina, as well as the oral cavity and throat. Not all cases of these rare cancers are linked to having an HPV infection.
  
  
• Low-risk HPV
  Infection with low-risk HPV doesn’t cause pre-cancerous changes in the cervix and doesn’t increase a woman’s risk of cervical cancer. But low-risk types of HPV can cause genital warts. The two low-risk types of HPV that are responsible for 90% of genital warts are HPV 6 and 11.
  
  HPV 11 can also cause recurrent laryngeal papillomatosis ( tumours that grow inside the larynx, vocal cords or respiratory tract) . This is a rare condition that can affect children, adolescents, and young adults.  

It is estimated that about 75% of sexually active men and women in Canada will have at least 1 HPV infection in their lifetime.

Symptoms of HPV infection

Most people will never know they have been infected because HPV usually doesn’t cause any symptoms (unless you are infected with the type that causes genital warts). This means you can get HPV and pass it along without ever knowing it. While an HPV infection can’t be treated, what it causes can.

• Pre-cancerous cervical changes can develop if there is a persistent or continuous high-risk HPV infection. Pre-cancerous cervical changes and cervical cancer can be treated.
• Genital warts caused by low-risk types of HPV can appear weeks or months after skin-to-skin sexual contact with an infected person. There are treatments for genital warts.

HPV and cervical cancer

Nearly all cervical cancers are caused by persistent high-risk HPV infection. In 2007, there were an estimated 1,350 new cases of cervical cancer and 390 cervical cancer-related deaths in Canada.

Cervical cancer screening

Regular cervical cancer screening is important for finding pre-cancerous changes in the cervix caused by HPV infection before cancer develops. Screening is done with a Pap test, which looks for changes or abnormalities in the cells of the cervix.

HPV testing

The HPV DNA test checks for the presence of high-risk HPV types. It helps identify women who presently have cervical lesions or are most likely to have pre-cancerous changes and are at risk of developing cervical cancer. The HPV test is not a replacement for the Pap test and is only effective for some women.

HPV vaccines 

Two vaccines have been developed to prevent HPV 16 and 18 infections. One is available in Canada. The other is currently being reviewed by Health Canada and is not yet available. The vaccines , however, should be viewed as a complement, not a replacement, for cervical cancer screening.

Suggested links

Health Canada - It’s Your Health: HPV

Public Health Agency of Canada - Facts and Information 

Last modified on:  21 May 2009

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