Image caption A third of adolescent girls in the US have received all three shots of the vaccine.

A US government medical committee has recommended the human papillomavirus vaccine for boys, to tackle the spread of the sexually-transmitted virus.

While the vaccine has been available to boys before, the vote means that injections are now likely to be covered under medical insurance.

Officials said a lower than expected rate of vaccination in girls encouraged them to reconsider the policy.

In boys, the vaccine protects against cancers associated with the virus.

The Advisory Committee on Immunization Practice, which advises the Centers for Disease Control, voted unanimously on Tuesday to recommend the vaccine for males ages 11 and 12.

Vaccination confusion

Dr Anne Schuchat, the director of the National Center for Immunization and Respiratory Diseases, told reporters vaccinating boys would provide a direct benefit against various cancers and genital warts, and would also potentially reduce the spread of the virus from males to females.

"[The] HPV vaccine is not being highly taken up among teen girls," she said.

As of last year, 49% of adolescent girls had received at least the first of the recommended three HPV shots, while only a third had had all three doses.

Dr Schuchat attributed the low rates for girls to confusion by parents that the vaccination is appropriate only when their daughter becomes sexually active. The vaccine works best if the shots are given before having sex.

According to the CDC, an estimated 50% to 80% of men and women are infected with HPV at some point in their lifetime, although most never develop symptoms.

But HPV is linked to almost 13,000 cases of cervical cancer yearly in US women, recent studies have shown increases in head and neck cancers linked to the virus.

The vaccine was drawn into the Republican presidential debates in September when candidate Michele Bachmann attacked Texas governor Rick Perry's executive order to require HPV vaccination for girls in the state.

Ms Bachmann told the audience she had heard it could cause mental retardation.

However, no such cases have been documented by US health authorities.