HPV Vaccine Prevents Cancer

The National Cancer Control Programme (NCCP) strongly encourages girls to get vaccinated against the Human Papilloma Virus (HPV). Most cancers of the cervix (neck of the womb) are caused by this virus. The HPV vaccine is effective in preventing cancer of the cervix and it is a safe vaccine. Every year in Ireland, approximately 300 women are diagnosed with cancer of the cervix and 100 women die from it.  This is the 7th most common cancer in women in Ireland. It can be prevented.

What are we doing to prevent cervical cancer?

Since 2011, all 1st year girls at second level schools or in similar age settings are offered free vaccination against HPV by the HSE. For the HPV vaccine to be effective, it is given prior to exposure to HPV.  This HPV vaccine prevents most cervical cancers, approximately 7 out of 10. 

The HPV vaccine also decreases the number of women with cells that are not normal in their cervix which can later become cancer, and therefore the number of women requiring treatment for these lesions. As a result, it will also decrease the number of women who go on to develop cervical cancer.

Ireland has a cervical cancer screening programme since 2008 (CervicalCheck). Cervical screening aims to detect cells that are not normal in the cervix which can become cancer and cervical cancer at an early stage when it is easier to treat.   At present over 6000 Irish women have pre-cancerous lesions detected and treated each year.  These could lead to cancer if left untreated.

What is HPV - Human Papilloma Virus?

HPV comprises a group of over 100 viruses.  In most cases, HPV is passed on by direct skin to skin contact during vaginal, anal or oral sex with someone who has been infected with HPV.  HPV infection is very common. It affects the majority of sexually active women and men and it is naturally cleared from the body within two years by more than 90 percent of people who become infected.  Sometimes HPV infection does not clear from the body naturally and the infection becomes chronic or persistent.  Chronic infection with high risk HPVs can lead to cell changes that, if untreated, may progress to cancer. 

HPV infection can also cause vaginal, and vulvar cancers in women; penile cancer in men; and anal cancer, cancer of the back of the throat (oropharynx) and genital warts in both men and women.

How does HPV infection cause cervical cancer?

HPV infection can damage the cells on the surface of the cervix, causing their appearance to change and lead to abnormalities in these cells over a number of years.  These abnormalities are known as Cervical Intraepithelial Neoplasia (CIN).  These changes can be categorised according to their severity.  Mild lesions are known as CIN1 and severe lesions are described as CIN2 and CIN3.  In some cases these more severe lesions can develop into cervical cancer. This is why HPV vaccination, before any HPV exposure, and cervical screening are essential in helping to prevent cancer.

How can the HPV vaccine help to prevent cervical cancer?

Virtually all cases of cervical cancer are caused by HPV.  HPVs associated with cancer are called oncogenic (cancer causing) or 'high risk' types.  HPVs that do not cause cancer are termed 'low risk' types.  Two types (16 and 18) are responsible for about 70% of all cervical cancer cases.  The HPV vaccine available in Ireland protects against these high risk strains of HPV (HPV 16 and 18), therefore preventing 70% of cervical cancers.  It also protects against two low risk strains (HPV 6 and 11) which cause approximately 90% of genital warts.  The vaccine is over 99% effective in preventing pre-cancers associated with HPV types 16 and 18 in young women and 99% effective in preventing genital warts associated with HPV types 6 and 11. 

Is cervical screening still necessary if vaccinated against HPV?

Girls that receive the HPV vaccines still have to be screened for cervical cell changes at the appropriate age (currently from 25 years of age) as the vaccine does not protect against all HPV types that can cause cancer.  Screening continues to be essential to detect pre-cancerous changes in cervical cells before they develop into cancer.  The combination of HPV vaccination and cervical screening can provide the greatest protection against cervical cancer

Are there other factors that can increase risk for cervical cancer?

Other high risk factors for development of HPV-related cancers include smoking, multiple sexual partners or a weakened immune system.

August 2016