According to a recent study, Cervarix was 90.4% effective in preventing lesions caused by HPV strains 16 and 18, based on an analysis that only required detection of the virus in the lesions. However, researchers found most of the lesions contained multiple HPV strains known to cause cancer, and GSK said the data showed Cervarix was 100% effective in preventing lesions caused by strains 16 and 18.

According to the study, the vaccine also provided significant protection against HPV strains 31, 45 and 52, which together account for about 12% of cervical cancer cases.

The European Committee for Human Medicinal Products in July recommended Cervarix for sale and marketing in the European Union. The committee reviewed data on the vaccine from clinical trials involving 30,000 women. A GSK spokesperson said Cervarix would go on sale in major European markets shortly. She added, "We intend to launch across Europe within the next few weeks."

GSK declined to comment on how much the company will charge for Cervarix or whether the European price would be above or below that in Australia, where the vaccine received regulatory approval in May. The vaccine is not likely to go on sale in the U.S. before 2008, Reuters reports. The company said a decision on its FDA application for Cervarix's approval in the U.S. will be given in January 2008.