Around 3,000 women each year undergo surgery after the discovery of changes in cervical cancer cells that, if left untreated, would lead to cancer. Pregnant women who have had this operation have an increased risk of miscarriage or premature birth.
There are many different strains of HPV and at least 12 strains can cause cervical cancer. Each strain is designated by a different number. The two most common ones are HPV 16 and HPV 18. In Norway these two strains together cause around 70 per cent of cervical cancer cases. Other types of HPV can cause warts around the genitals/anus, but do not cause cancer. Almost all genital warts are caused by HPV 6 or HPV 11.
HPV is transmitted extremely easily through sexual contact and normally produces no symptoms. Most people will have an HPV infection at some time in their lives, most commonly at a young age. The HPV infection disappears by itself in most cases. A long-lasting infection with a cancer-causing HPV strain can result in cell changes that may lead to cervical cancer. This process normally takes 10 to 30 years.
In autumn 2009 the HPV vaccine was introduced into the Childhood Immunisation Programme and is offered to all 7th grade girls in Norway.