Immunising every 12-year-old girl with a new vaccine would cut the number of deaths from cervical cancer in the UK by more than 75%, the manufacturers claim today.

GlaxoSmithKline, the British company slightly trailing Merck in the race to produce the first cervical cancer vaccine, will produce statistics at a conference in Prague to estimate that 100% vaccine coverage in the UK would cut the death toll from the disease from 1,093 deaths a year to 262. Their figures also suggest the number of women developing cervical cancer at all would be reduced from 2,841 to 682.

The studies into the vaccines show that they are most effective in young girls who are not yet sexually experienced, which is why it is suggested that immunisation should take place at age 12.

GSK admits that there is no likelihood of every 12-year-old being vaccinated. Even if the NHS decided to take up the vaccine and offer it to all schoolgirls, there is likely to be a substantial number of parents who would turn it down.

Cervical cancer is, in effect, a sexually transmitted disease, caused by infection with the human papilloma virus and more likely the more sexual partners a woman has. The vaccine protects against HPV infection. Many parents, particularly in the US where Merck will launch first, are expected to resist any suggestion that their child should be vaccinated against a sexually transmitted infection.

But even with 80% coverage, GSK says its computer modelling shows that deaths from the cancer should drop by 61%.

The company also says that vaccination would reduce the number of abnormal smear tests during cancer screening by 52.4% and it would cut the need for diagnostic colposcopies - a tissue-sampling procedure to establish whether an abnormal smear is really cancer - by 54.8%.

GSK's vaccine offers protection against the two most common strains of the virus implicated in cervical cancer, HPV 16 and 18. However, at the International Papilloma conference in Prague today, Merck will claim that its vaccine may offer protection against even more strains of HPV.

It has already been shown to protect against four strains of HPV - HPV 6, 11, 16 and 18. The latest study suggests, the company says, that it can neutralise HPV 31 and 45 as well. This would mean that it protects against 85% of the strains responsible for cervical cancer.

Both companies are positioning themselves to take advantage of a potentially huge market in the developed world, where cancer is the most feared disease. The greatest need for such a vaccine, however, is in developing countries where there are no screening programmes for cervical cancer and far more women die of the disease.