Gardasil can also be given to men as a way to prevent genital warts, a study presented Thursday at a medical conference in Europe revealed.

The study, funded by Gardasil’s manufacturer Merck & Co., involved about 4,000 males ages 16 to 26 from nearly 20 countries. It showed the vaccine was 90 percent effective in preventing genital warts, with only 15 cases of persistent infection in a vaccinated group of males as compared to 101 cases in a group that was given a fake vaccine.

“This is groundbreaking data. To demonstrate that Gardasil prevents infection and disease at a very high level in males - that's the other half of the world,” said Anna Giuliano, professor of medicine and epidemiology at University of South Florida, who co-authored the study.

Two years ago, Merck made headlines when it was approved by the Food and Drug Administration as a way to protect against cervical cancer.

Approximately 40 countries have approved Gardasil for men, even though no clinical trial showed the vaccine prevented penile cancer or other HPV-associated cancers in males. Also, there is no medical proof indicating that it prevents men from spreading the virus to women.

The cervical cancer vaccine was licensed for use in girls and women aged 9 to 26. However, to be most efficient, Gardasil should be administered to girls before they are sexually active because there are more than 100 strains of the HPV and more than 30 of those strains can be spread through sex. The results of the new study clearly show that Gardasil might be closer than ever to get the FDA clearance for use in boys as well.