ATLANTA — A government panel wants young boys as well as girls to get the controversial HPV vaccine, in part to prevent them from spreading the sexually transmitted virus to girls.

For the last five years the HPV vaccine has been recommended for young girls to protect them against cervical cancer and genital warts. But the vaccine has been slow to catch on — only about a third of adolescent girls have gotten all three shots.

Experts say the HPV vaccine could protect boys against genital warts and some kinds of cancers. But they also say vaccinating 11- and 12-year old boys could help prevent them from spreading the human papilloma virus to girls.

The Advisory Committee on Immunization Practices unanimously voted the recommendation Oct. 25. Federal health officials usually adopt what the panel says and ask doctors and patients to follow the recommendations.

The vaccine has been licensed for use in boys for two years but the vote was the first to strongly recommend routine vaccination. Officials acknowledged the disappointing rate in girls encouraged them to take a new, hard look.

But if the expensive HPV vaccine has been a tough sell to the parents of girls, it may be even tougher for boys.

Last year, just 49 percent of adolescent girls had gotten at least the first of the recommended three HPV shots. Only a third had gotten all three doses.

“Pretty terrible,” said Dr. Anne Schuchat, a U.S. Centers for Disease Control and Prevention administrator who oversees the agency's immunization programs.

She attributed the low rates for girls to confusion or misunderstanding by parents that they can wait until their daughter becomes sexually active. It only works if the shots are given before a girl begins having sex.

The vaccine is approved for use in boys and girls ages 9 to 26; but it is usually given to 11- and 12-year olds when they are scheduled to get other vaccines.

The committee also recommended the vaccination for males 13 through 21 years who have not been vaccinated previously or who have not completed the three-dose series.

The vote follows recent studies that indicate the vaccine prevents anal cancer in males. A study that focused on gay men found it to be 75 percent effective. But while anal cancer has been increasing, it's still a fairly rare cancer in males, with only about 7,000 cases in the U.S. each year that are tied to the strains of viruses targeted in the HPV vaccine.