HPV ranks as the leading cause of cervical cancer in women, but it can also cause genital warts, penile cancer, anal cancer and other malignancies in men.
Gardasil®, which was approved by the FDA for girls in 2008 and boys aged 9 through 26 in 2009, was shown to be 90 percent effective in older teenage boys and young adult men.
A Centers for Disease Control and Prevention advisory panel voted against routinely vaccinating boys with HPV vaccine, though they recommended that 11- and 12-year-old girls receive the shots as part of school vaccination efforts. The panel found that the cost-to-benefit ratio of vaccinating males was not favorable if more than 80 percent of females were vaccinated.
Only about one-third of the teenage girls who begin the series of three shots, which cost about $375, actually finish the regimen, either because of associated costs, misinformation or lack of commitment to the process. It is not yet known how much protection only one or two doses of the vaccine offers, so it's important for individuals to follow through with all three doses.
Study author Anna Giuliano said the benefit for vaccinating males is two-fold: not only will this cut their risk, reducing infections in men and boys will also prevent them from passing it to girls.
Researchers also saw some reduction in precancerous penile lesions in the 4,000 men and boys aged 16 to 26 from different countries who were randomly assigned to the trial, although they said it's impossible to know if this reduction was due to the vaccinations.
Almost all penile malignancies are skin cancers, with the most common being squamous cell carcinoma.