New vaccines against HPV, the virus that causes most cases of cervical cancer, could reduce the number of cases -- and deaths resulting from the disease -- by as much as 76 percent, new research indicates.

If 80 percent of 12-year-old girls were immunized, cases and deaths could be reduced by 61 percent, the researchers said.

Cervarix is only one of several vaccines developed to prevent the virus, which infects as many as half of all women before they reach 30 years of age, according to estimates.

Cervical cancer is a major global health problem, says GlaxoSmithKline, with nearly half a million new cases occurring each year worldwide. It is the second most common cancer and the third leading cause of cancer deaths in women. Each year, an estimated 270,000 women die from the disease. It is the leading cancer killer of women in the developing world.

Almost 3,000 women in the UK are diagnosed with cervical cancer every year and more than 1,000 die from the disease. It is the second most common cause of cancer in women under 35 years old.

Cervarix prevents the two most high-risk HPV strains, known as 16 and 18.

Another study presented at the conference in Prague suggests that Merck's HPV vaccine, Gardasil, may provide even more protection, by preventing not only the two strains responsible for most cervical cancer, 16 and 18, but also two other types, 31 and 45, which account for another 9 percent of cases.

Gardasil was approved by the US Food and Drug Administration in June. It has also been approved by the European Medicines Agency. Cervarix has not yet been approved by the FDA; EMEA approval is expected soon.

In some regions of the world, the US in particular, the HPV vaccines have sparked controversy because they are most effective if administered before a woman becomes sexually active. Some health experts recommend giving it to girls as young as nine years old. Opponents -- among them the Catholic Church -- argue that such a plan could encourage girls to engage in sex at younger ages.