U.S. pharmaceutical giant, Merck, says a recent study showed a new experimental vaccine to be 100 percent effective for the short-term in blocking two viruses that can cause cervical cancer in women.

Merck said Thursday, its Gardasil vaccine blocks infection from Human Papillovirus 16 and 18 - which both cause about 70 percent of all cases of cervical cancer.

The drug company said the trial among 12,000 women from 13 countries also found that Gardasil blocks cervical lesions that could become cancerous.

Sexually transmitted viruses known as HPVs strike about 75 percent of all women at some time in their lives, and kill almost 300,000 women without healthy immune systems ever year.

A separate study earlier this year found that a vaccine developed by British firm, GlaxoSmithKline, was 92 percent effective in blocking cancer from four HPVs.

Some information for this report provided by AP and Reuters.