HPV virus and cervical cancer
According to international statistics, cervical cancer is the second commonest cancer of women. Each year, in Greece, more than 400 women will develop cervical cancer. That means that more than one woman per day will face a very upsetting situation.
We know that the cause of cervical cancer is a persistent infection by some oncogenic HPV virus type. HPV is a virus that is sexually transmitted. The family of HPV virus consists of many subtypes. HPV infection is very common but, luckily, evolution of the infection to cancer is very rare.
Until recently, cervical cancer prevention was based, solely, on the smear (Pap) test. Currently, we have in our disposal another tool for the prevention of the lesions caused by HPV virus. This is the HPV vaccine which, in Greece, is provided for free by the State for girls and women age 9- 18. The vaccination is included in the National Vaccination Program.
What is HPV?
HPV, or Human Papilloma Virus, is the common name of a family of viruses with many subtypes.
Different HPV virus subtypes are classified as high or low risk, depending on the lesions they cause. For example, some types (like type 6 and 11) cause warts. Other types (like 16 and 18), are associated with cervical cancer.
In 99% of the cases, cervical cancer happens as a result of a past, high risk subtype HPV virus persistent infection. Usually, HPV infection does not cause any obvious symptoms.
How is HPV transmitted?
HPV virus is very common and is easily transmitted through sexual contact. It is estimated that around 50- 70% of the population will be infected by the virus at some point in their lives. Most of the times, the virus does not cause any lesion because the immunologic system of our body clears the infection. Occasionally, the infection will persist and can lead to health issues.
Does the condom protect me fully?
Using a condom during sexual contact can protect against the HPV infection. However, since the condom does not cover the whole genital area and because, often, is not used from the start of the intercourse, it cannot protect 100% against HPV contamination.
The different types of HPV virus and what they cause
There are more than 100 different subtypes of the HPV virus, with more than 40 ones affecting the genitals.
Infection with some HPV types that are called high risk can lead to abnormal tissue growth and cellular changes that can cause, in the future, cervical cancer. Such subtypes are, for example, number 16, 18, 31, 33, 34, 45, 52 and 58. These subtypes account for more than 90% of the cervical cancer cases. Subtypes 16 and 18 are the commonest ones. Apart from cervical cancer, the oncogenic subtypes of the HPV virus can also cause cancer of the vagina and vulva but also anal cancer, cancer of the penis and part of the mouth/ neck (oropharynx).
Infection of the organism with other types that are characterised as low risk can cause the appearance of warts in the genital and anal area but also on the skin. It can also cause papillomas of the larynx (voice box). Such subtypes are, for example, the types 6, 11, 40, 42, 43, 44, 53 and 54. The most common of them are subtypes 6 and 11 which account for more than 90% of warts.
How does the HPV vaccine help?
There are two commercially available vaccines. One that protects from the oncogenic types 16 and 18 and one that additionally protects from the oncogenic subtypes 31, 33, 45, 52 and 58, but also from the non-oncogenic subtypes 6 and 11 that cause warts.
Is the vaccine safe? Does it have any side effects?
The HPV vaccine is safe. It is available in the market for many years and millions of vaccinations now. It can rarely cause local side effects like pain and skin redness at the vaccination site. Headache or some minor ailment can also be experienced.
Special precaution is needed in case other, chronic medical conditions exist or if there is a history of a severe allergic reaction (anaphylaxia). If this is the case, we should be informed in advance.
How is the vaccine administered?
Dosage depends on the vaccination age. For girls younger than 15 years two shots are enough; for older girls and women three shots are needed in order for the body to produce enough antibodies. The vaccine is given intramuscularly.
It is important that the vaccination schedule is completed so that enough antibodies are produced.
Annual screening test and the HPV vaccines
The annual screening test for cervical cancer with the smear (Pap) test is an effective way of identifying lesions of the cervix long before they develop into cancer. It is scientifically proven that prompt diagnosis and proper treatment of the cervical lesions can save lives. With regular screening approximately three out of four cases of cervical cancer can be prevented.
Those women that have been vaccinated should not neglect their annual screening test. Despite the fact that the vaccine is anticipated to help reduce the cases of cervical cancer, women are not protected from the effect of all causes of cervical cancer unless being screened regularly.