HPV vaccines

Professor Alison Fiander and Dr Amanda Tristram answer questions about HPV vaccines.

How can a vaccine prevent cervical cancer?

If HPV is so common, and it affects nearly all of us, why don't more women get cervical cancer?

Can these vaccines help if you already have an abnormal smear test or cervical cancer?

Is this the same virus that causes genital warts?

Will the vaccine protect against genital warts?

When will be the best time to be vaccinated?

How long will the protection last for?

Will being vaccinated prevent all cases of cervical cancer?

Is the vaccine available yet?

What about men?

Would you encourage you daughter to be vaccinated?

What do you think is the most important message to get across about HPV vaccines?

How can a vaccine prevent cervical cancer?  

Cervical cancer is caused by a very common virus, called human papillomavirus (HPV). Most women are infected by HPV at some point in their lives, but never know they have been infected. HPV is usually cleared (without treatment) by the body's immune system, like other viral infections such as a cold. We know, but not why a small percentage of women do not clear the infection, which can remain 'dormant' (inactive) in their bodies sometimes for many years. This is the reason why it is important for women to attend for regular screening.

In some women, however, the virus may lead to the development of cancer. Early trials have shown that vaccination can prevent infection with 'high risk' types of HPV that cause cervical cancer. They have also shown a reduction in abnormal smears, although none of the trials conducted are long enough yet to show a reduction in cancer.

If HPV is so common, and it affects nearly all of us, why don't more women get cervical cancer?  

The majority of women clear the infection through their immune systems but for those who do not, regular smear tests can pick up abnormalities in cervical cells  before a cancer develops. These abnormal cells can then be removed and in the majority of cases this is highly successful. In a very few women, changes occur more rapidly, in the interval between cervical smear tests, or occasionally the changes are not detected by a smear test.

Can these vaccines help if you already have an abnormal smear test or cervical cancer?

At the present time, there is no vaccine that can treat women after they have been affected.

Is this the same virus that causes genital warts?

No. Cancer and genital warts are caused by different types of HPV, so having genital warts does not mean that you are more likely to get cancer. There are about 100 types of HPV, the majority of which do not cause any health problems. Research has identified specific HPV types that are 'high risk' and 'low risk' for cervical cancer. The most common types that cause cervical cancer are 'high risk' HPV types 16 and 18 while the 'low risk' types that cause genital warts are HPV types 6 and 11.

Will the vaccine protect against genital warts?  

The first vaccine to protect against HPV received its European license in October, 2006. It is called Gardasil and will protect against four HPV types: the two most common HPV types that cause cervical cancer, HPV types 16 and 18 as well as the two most common HPV types that cause genital warts, HPV types 6 and 11. The other vaccine, called Cervarix is expected to be licensed in 2007 and will protect against HPV types 16 and 18 only.

When will be the best time to be vaccinated?

Women will need to be vaccinated before they come into contact with the virus.  As the virus is transmitted by skin to skin contact, usually by sexual activity, this age will vary. In practical terms, probably the most effective and easiest way to reach everybody is for girls to be vaccinated either just before leaving primary school or during their first year at secondary school.

How long will the protection last for?

HPV vaccination has been shown to prevent infection and pre-cancer for at least 5 years but it is expected to last longer. Ongoing studies will show how much longer you will be protected for and whether booster shots will be required.

Will being vaccinated prevent all cases of cervical cancer?  

The currently licensed vaccine, Gardasil protects against the two most common HPV types that cause cancer, types 16 and 18. It has been estimated that this will prevent about 75% of cervical cancers. You should note however, that it is important to attend for regular screening even if you have been vaccinated so that abnormalities caused by other HPV types may be detected.

Is the vaccine available yet?

The National Prescription Research Centre (NPRC) carries out checks on the pricing of NHS prescriptions, both on a routine basis and at the request of individual pharmacy contractors.

What about men?

Men rarely suffer problems from the HPV types that cause cancer.  It is has not been proved whether or not vaccinating men can help prevent women getting the infection.

Would you encourage you daughter to be vaccinated?

Yes, I would because we know that nearly all women will get an HPV infection at some point in their lives and I would want to protect my daughter as far as possible against the risk of abnormal smears and cervical cancer.

What do you think is the most important message to get across about HPV vaccines?

HPV vaccines have the potential to reduce the number of cases of cervical cancer and the number of women who have to be treated for abnormal smears in generations to come.  For women who are already part of the screening programme, the best protection against cervical cancer is to continue going for regular smear tests.

Professor Fiander is Chair of Obstetrics & Gynaecology and Dr Tristram is a Sub-specialist Fellow in Gynaecological Oncology at Cardiff University

In 2004, Women in Government (a US non-profit organisation of women state legislators) launched the Challenge to Eliminate Cervical Cancer Campaign

Last Updated: 03 Apr 2008