Selasa, 01 Januari 2008


Cervical cancer vaccine
Written by Dr David Delvin, GP

© PhotoDisc
Vaccines protect against the types of HPV that cause most cases of cervical cancer.
2007 heralded the arrival of two new vaccines to prevent cancer of the cervix (neck of the womb): Gardasil and Cervarix. They both work by protecting against the human papilloma virus (HPV) that causes most cases of cervical cancer.

What is cervical cancer?

Cervical cancer is the second most common malignancy among women worldwide, with about 500,000 cases a year. In developing countries it is the main cause of cancer deaths in women, and around 250,000 women die each year because of it.

In the UK the national smear testing service that screens for HPV has led to a great decrease in the number of deaths from cervical cancer. In 2006 around 1000 women died from cervical cancer, mainly because they did not attend smear tests.

The main risk factors for cervical cancer are:

* smoking

* living in a poor area (cervical cancer is more common in the north of England than in the affluent south)

* a partner who has a manual job

* having started sex early in your teenage years

* having multiple sex partners

* multiple pregnancies.

But any woman who has ever had sex is at some risk of cervical cancer.

What is HPV?

Human papilloma virus (HPV) is a virus that is passed on by sexual activity. It needn’t be actual sexual intercourse: HPV can also be transmitted by deep petting (genital love play).

It's thought more than 80 per cent of British females get HPV at some point in their lives. But what usually happens is the virus doesn’t cause a cancer, and after some time the body eventually defeats it and gets rid of it.

There are more than 100 types of HPV. Some types of HPV are associated with genital warts. Others are linked to cancer of the vulva, vagina, anus, penis and throat.

Only a few types – notably numbers 16 and 18 in the UK – are capable of producing cervical cancer. It usually takes 20 years or more for cancer to develop.

The peak age for cervical cancer in the UK is 35 to 40, though you can get this type of cancer well into old age.

How can you tell if you have HPV?

HPV does not produce symptoms when you get it, so you have no way of telling whether it is present in your body unless you have a smear test.

Pap smear tests should detect the cancer long before it produces any symptoms. If HPV is detected by a smear test, it can usually be treated and cured. As a rule, this will be long before it can do you any harm.

What are the new vaccines?

There are two new vaccines against HPV: Gardasil and Cervarix.

Gardasil has been licensed in over 75 countries, including Britain. It works against HPV types 16, 18, 6 and 11. These strains of virus cause most of the cases of cervical cancer in the UK, so if given early enough Gardasil would prevent the majority of these cases.

But because it doesn't protect against all strains of HPV, it cannot prevent all cervical carcinomas. It also gives some protection against genital warts that are also caused by HPV.

The other vaccine, Cervarix, has been approved by the health authorities in Australia and is awaiting approval in America and the UK. It protects against HPV types 16 and 18, but no others. So again, it cannot offer a woman 100 per cent protection against cervical cancer.

How are they taken?

Both vaccines are given as a course of three injections, over a period of about six months.

How long does protection last?

At the moment, we know that the protection offered by the vaccines lasts at least five years. Nobody can yet say whether it will last for life.

Are there any side-effects?

Like virtually all medications, the two new vaccines can have side-effects. While these don’t appear to be serious, it’s possible that more significant side-effects might emerge in the long term, as is the case with any new treatment.

At present, the most common adverse effect is soreness at the injection site, which is not a major problem. The jab can also cause skin irritation and slight fever.

Rare ill-effects include joint pain and the skin eruption called urticaria (hives). Very rarely, the jab can cause wheezing.

It is not known whether the drug will be safe for use during pregnancy. Certainly, no pregnant woman should consider having it at present.

Who should have the vaccine?

Currently, health authorities regard these vaccines as a preventative measure, so the focus is on giving the vaccine to young teenage girls well before they start having sex. In Australia there are plans to give it to teenage boys.

In Britain the vaccination will be offered to all 12 and 13-year-old girls from September 2008. In autumn 2009 a two year catch-up campaign will start for girls up to 18 years of age.

Adults and the vaccine

Many women have read newspaper reports about the new vaccines and thought it would be a good thing for their health.

But there seems to be little point in an adult woman having the jab. Why? Because it’s probably too late to protect against the HPV virus, which may well have entered your body years before.

For the moment, adult females should continue to rely on Pap smear tests to protect them from HPV. It seems probable that this will be so for at least the next 20 years.

A case could perhaps be made for administering it to a woman who is a virgin, but who is now planning to embark on an active sex life. The same could be said of a woman in her early twenties who has had very little sexual activity so far.

In practice, if you are an adult it is very unlikely that your GP could get approval for giving you the vaccine - or would even want to get it. The jab is expensive, costing about £80 a dose.

If you really want the vaccine, your only option is to go private - if you can find a gynaecologist who is willing to administer it.

You may be surprised to hear that some adult males have gone to private doctors to get the vaccine. These are gay men, who want to try to protect themselves against genital warts and possibly anal cancer.

What about objections to the vaccines?

In the USA there have been quite vociferous moral objections to the use of the vaccine in the early teens. This is because it is felt by some people that giving teenagers the jab is equivalent to handing them permission to have sex.

In Britain recent surveys have shown that about three quarters of parents would be pleased for their daughters to have this jab, once they realise its purpose is to prevent cancer.

Will the vaccines eradicate cervical cancer?

One of Britain’s greatest experts in the field of cancer-causing viruses, Professor Margaret Stanley, says the introduction of the vaccines 'really does look like the beginning of the end for HPV-associated disease in women'.

However, Professor Stanley is open about her possible bias as a consultant for the firms that make the vaccines.

Other experts believe the many types of HPV are so rife, women are going to need to continue to have smear tests well into the 21st century.

Do you still need to go for smear tests after having the vaccine?

Even if you have the vaccine, you must continue attending for regular smears. This is because the jab cannot protect you against all strains of HPV.

HPV has no symptoms - so don’t think 'I haven't got any symptoms and I feel perfectly well, so I don’t need smear tests.' You do.

Similarly, if your 12-year-old daughter is given the vaccine, she too will need to have smear tests throughout her adult life.

Last updated 01.11.2007

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