By Caroline Ryan
BBC News Online health staff in Copenhagen
Just one type of the sexually transmitted virus linked to cervical cancer causes almost two-thirds of cases, researchers have found.
A vaccine could be highly effective
The Human Papillomavirus (HPV) is the main cause of the cancer, and around 15 high-risk types have been identified in all.
But Spanish researchers told the European Cancer Conference (ECCO) in
Copenhagen, Denmark, that a type called HPV 16 accounts for around 64% of cases in the US and Europe.
The second most common variety, HPV 18, accounts for around another 8% of cases.
Scientists around the world are currently developing vaccines to protect
against the HPV virus, and deciding which varieties they should act against.
The first vaccine could be ready in around three years.
The drug company GlaxoSmithKline plans to start advanced international trials of its vaccine next year.
It will be targeted at thousands of women aged 15 to 25 in six or seven countries, including the UK.
Ultimately, the plan is to give the vaccine to girls as young as 11 or 12, and possibly to boys, who can carry the infection and transmit it through unprotected sex.
It is estimated that up to 20% of women aged 18 to 22 in the UK carry a variety of HPV.
In Europe, there are 65,000 new cases of cervical cancer each year causing
Researchers from the Institut Catala d'Oncologia in Barcelona looked at data
from 3,000 of cases of cervical cancer from around the world.
Dr Xavier Bosch who led the research, told BBC News Online: "We concluded that, globally, HPV 16 accounted for 56 to 62% of cervical cancers - in Europe, it was more like 64%."
He said it was important to get the right combination in the vaccines that
were being developed.
"In Europe and North America a vaccine including HPV 16 and 18 - the most
common types of the virus - would prevent 72% of cases among the
"A vaccine containing types 16, 18, 33, 31 and 45 would cover 84% of the
"But 16 and 18 have to be there."
He admitted that research into a cervical cancer vaccine was still at a relatively early stage, and would be expensive to introduce.
But he added: "The gains in the longer term would be huge, both in terms of healthcare costs and in women's quality of life.
"In the meantime, participation in effective screening programmes, particularly if they include HPV testing, can detect and prevent many potential cases of cervical cancer at a very early stage."