U.S. advisors on Thursday agreed unanimously on the need for the Food and Drug Administration to approve a cervical cancer vaccine developed by Merck and Co., which says the vaccine could reduce worldwide deaths from the cancer by two thirds.

A FDA advisory committee voted 13-0 for the vaccine, named Gardasil. It is the first vaccine to protect females from the sexually transmitted human papilloma virus (HPV) which causes most cervical cancer. The cancer kills about 300,000 people worldwide each year.

The advisors said Merck's studies showed that Gardasil could prevent early-stage cervical cancer and pre-cancerous lesions in females aged 9 to 26.

The FDA usually follows the recommendation of its advisors. A final decision is expected by June 8.

The vaccine works only against four types of HPV, indicating a need for women to continue regular screening for cervical cancer.

The four HPV types are held responsible for more than 70 percent of cervical cancer cases and 90 percent of genital warts.

Merck said a global use of Gardasil could cut annual deaths from cervical cancer to about 90,000. In trials, three doses of the vaccine over six months provided protection lasting five years.

Merck will do further studies to assess the need for booster shots.  The high anticipated cost of the vaccine, between 300 and 500 U.S. dollars, may possibly impede widespread vaccination campaigns. Merck is seeking to license Gardasil in more than 50 countries.