Human papillomavirus (HPV) is a common cause of infection but usually causes no symptoms. Infection with some types of HPV can cause cancer of the neck of the womb (cervix). Cervical cancer takes many years to develop after the infection with HPV. Genital warts are also caused by HPV. Immunisation against HPV should dramatically reduce cervical cancer cases in the future and lead to fewer cases of genital warts. It may also reduce other cancers thought to be sometimes due to HPV. Immunisation against HPV was introduced in the UK for girls in 2008. Women are still advised to attend for cervical screening tests, even if they have been immunised against HPV.
What is human papillomavirus (HPV)?
HPV is the name given to a group of germs (viruses) that can affect the skin and mucosae. The mucosae are the moist membranes that line different parts of the body, including the mouth, throat and genital area.
There are over one hundred types of HPV and about 40 of these can affect the genital area. Some types of HPV can cause skin warts and verrucas but many types do not cause any problems or harm at all.
Both men and women can have HPV. There are certain risk factors for HPV infection that include:
- Multiple sexual partners.
- Early age of first having sex (sexual intercourse).
Most women will have an HPV infection at some time during their lives, usually without even knowing it. Some types of HPV are known to increase the risk of developing particular cancers. These are known as cancer-causing (oncogenic) or high-risk subtypes. About 9 in 10 infections with HPV will clear completely from the body within two years by the immune system - it is a self-limiting infection for most people. There is no treatment for HPV itself.
What is the link between human papillomavirus (HPV) infection and cervical cancer?
Cervical cancer is one of the four most common types of cancer in women in the world as a whole. Since the cervical screening programme began, however, it is much less common than this in the UK. It now accounts for about 1 in 100 deaths in women from cancer. It kills just over 900 women every year in the UK. Most types of HPV do not cause any symptoms or diseases. However, two types, HPV16 and HPV18, are involved in the development of most (three quarters of) cases of cancer of the neck of the womb (cervix).
HPV infection with types 16 and 18 can cause cells in the cervix to change gradually over time. This may lead to pre-cancerous cells forming. These changes can develop into cancer over time if not treated. The pre-cancerous change in the cells is known as cervical intraepithelial neoplasia (CIN) and is discussed in a separate leaflet called Cervical Cancer. Having these types of HPV infection does not mean that you will definitely go on to develop cancer of the cervix. However, your risk of developing cancer of the cervix is much increased with these infections. This is why checking for HPV has recently become part of some smear tests. If you have HPV found in your smear sample, doctors will test you more regularly, and you are more likely to need treatment for minor changes. At present checking for HPV is done on your smear test, but it can be tested from a urine sample. It may be in the future that this could be used for the screening programme, but more studies need to be done.
HPV infection with types 16 and 18 is passed to other people by sexual contact, usually through having sex. It is more common, therefore, in those people who have had several different sexual partners.
Unfortunately, the use of condoms does not seem to protect very well against HPV transmission. Condoms prevent some cases, but not all. Safe sex with a condom is still advised, as condoms prevent against many other sexually transmitted infections (STIs) such as chlamydia and human immune deficiency virus (HIV).
Human papillomavirus (HPV) and other diseases
HPV and genital warts
Genital warts are the most commonly diagnosed STI. Two types of HPV (types 6 and 11) are the cause of about 9 in 10 cases of genital warts. These types of HPV do not cause cervical cancer. See separate leaflet called Anogenital Warts for more information.
HPV and other cancers
It is thought that HPV may cause as many as one in twenty cancers. As well as cancer of the neck of the womb (cervix), it can cause cancer in other genital areas. These include cancers of the penis, vulva, anus and vagina. HPV can also cause some cancers of the neck and throat.
Human papillomavirus (HPV) vaccines
Two HPV vaccines are available in the UK: Cervarix® and Gardasil®.
This known as a bivalent vaccine, meaning it protects against two strains of HPV. Cervarix® protects against HPV16 and HPV18 and so is aimed to reduce (in time) the number of cases of cervical cancer. When the UK first started immunising young women against HPV, this was the vaccine chosen.
This a quadrivalent vaccine, meaning it protects against four strains of HPV. Gardasil® protects against HPV16, HPV18 and HPV6 and HPV11. This means that it also protects against genital warts as well as cervical cancer.
In November 2011, the Department of Health announced that the UK HPV immunisation programme would switch to using Gardasil® from September 2012. The decision to change to Gardasil® was made because it protects against genital warts and cervical cancer. This is felt to be the safer option, as condoms only stop about half of cases of genital warts being passed on. There are around 100,000 new cases of genital warts per year in the UK, costing the NHS nearly £17 million to treat in England alone.
Is the human papillomavirus (HPV) vaccine effective?
Studies have shown that the HPV vaccines are very effective at stopping cancer of the neck of the womb (cervix) developing. In clinical trials, the vaccine was over 99% effective at preventing pre-cancer or cancer of the cervix associated with HPV types 16 or 18 in young women. Gardasil® is also 99% effective at preventing HPV6- and HPV11-associated genital warts.
The vaccine has been shown to work better for people who are given the vaccine when they are younger, before they are sexually active, compared to when it is given to adults. However, the HPV vaccine still does not completely protect against all HPV infections and it is not a treatment for HPV. Trials have shown that the HPV vaccine is effective against HPV for up to ten years. More trials are being done to find out if it is effective for longer than this.
The HPV vaccines do not prevent all cases of cervical cancer (as not all cervical cancers are caused by HPV16 and HPV18). So, it is still important that women attend for their cervical screening tests when invited. See separate leaflet called Cervical Screening (Cervical Smear Test) for more information.
What are the current recommendations regarding the human papillomavirus (HPV) vaccine?
The immunisation programme started in the UK in 2008.The aim of the HPV immunisation programme is to protect females before they reach an age when the risk of HPV infection increases. This should then reduce their risk of cervical cancer. Initially this was done with three doses, spread out over a few months. However, studies have shown the vaccine is just as effective when it is given in two doses. These need to be at least six months apart, and no more than two years apart.
Currently the Department of Health recommends the first dose of the vaccine should be given to girls aged 11 to 14 years of age. This means school year 8 in England and Wales, S1/S2 in Scotland, and school year 9 in Northern Ireland. The second dose should then be given 6 months-2 years later. The vaccine is given at school. The vaccine is given by injection in the upper arm or thigh.
This two-dose schedule began in September 2014. Girls who had already started the three-dose schedule should complete the schedule they began. Girls over the age of 15 starting the vaccination should have the original three-dose schedule. Girls over the age of 18 are not usually vaccinated. However, if they started their vaccinations before the age of 18 and didn't finish the course, this can be completed. This is done by the nurse in their GP surgery. Girls under the age of 18 coming to live in the UK from other countries should also have the vaccination.
At this time boys are not part of this programme. They are not given the HPV vaccine in schools. However, some other countries do vaccinate boys as well. This is because it protects them against genital warts and some types of cancer, as discussed above. Some experts feel boys in the UK should have the vaccine too. So, this may change in the future.
Are there any side-effects from the vaccine?
The human papillomavirus (HPV) vaccine is generally very safe. Serious problems caused by the vaccine are rare.
It is quite common to have mild side-effects for a day or so. Most common side-effects are some mild pain, swelling, redness, itching or bruising around the site of the injection. Other common side-effects are headache, aching muscles and tiredness. Less common side-effects include slightly raised temperature, being sick (vomiting), dizziness, fainting, diarrhoea and muscle aches. More rarely, people can develop hives (urticaria).
You should not have the vaccine if you are have had an allergic reaction to a previous HPV vaccine. It is safe in people who have egg, yeast or nut allergies. You should not have it if you have a high temperature or are generally ill. However, it is still possible to be immunised with the HPV vaccine if you have a common cold. Taking the contraceptive pill does not interfere with the vaccine.
Do I still need to have cervical screening tests?
Yes. You should still attend for your regular cervical screening tests, even if you have received the human papillomavirus (HPV) vaccine. This is because the vaccine does not guarantee complete protection against cervical cancer. Cervical screening tests are still important as:
- Immunisation with the HPV vaccine will take several years to reduce the chances of developing cervical cancer.
- The vaccine does not protect against all HPV types.
- Not all cases of cervical cancer are caused by the high-risk HPV16 and HPV18 strains.
- Not all women will have had the vaccine. Women who do not have the vaccine will not be protected at all against cancer of the neck of the womb (cervix).
It can take between 10 and 20 years for cancer of the cervix to develop after having an infection with HPV. This means that the benefits of the HPV immunisation programme will take many years to be shown.
Do I need a special test to see if I have human papillomavirus (HPV)?
HPV testing done at the moment is called 'HPV triage', as it sorts (triages) women according to whether they have HPV. In some parts of the UK if you have a mildly abnormal cervical screening test (so-called borderline changes, or mild dyskaryosis), an HPV test is automatically done on the sample. In other parts of the UK an HPV test is done on the repeat follow-up sample. This helps doctors decide whether you need to have a more specialised examination of the neck of the womb (cervix), called a colposcopy. See separate leaflet called Colposcopy for more information.
An 'HPV test of cure' is also being introduced for women who have treatment for abnormal (pre-cancerous) cells at colposcopy. It can allow a decision to be made regarding how often future cervical screening tests need to be performed on those women.
Further help & information
Dr Louise Newson
Dr Mary Harding
Prof Cathy Jackson