Vaccination against human papilloma virus was recommended for U.S. girls almost five years ago. In October, a government advisory committee also recommended routine vaccination for boys ages 11 and 12.
But vaccinating girls only makes the most sense, researchers said Tuesday.
Using mathematical models, researchers in the Netherlands found vaccinating girls is the best way to reduce heterosexual transmission because girls have the highest prevalence of the virus. Immunizing the group with the highest prevalence achieves the largest population-wide reduction of the virus.
Certain strains of HPV cause genital warts. The sexually transmitted disease can cause cervical cancer in women and anal and penile cancer in men as well as oropharyngeal cancers in both sexes.
Vaccinating males against HPV is sometimes promoted because it can protect boys from some types of cancer and because it helps create "herd" immunity in the population. But, the authors wrote: "We show that, once routine vaccination of one sex is in place, increasing the coverage in that sex is much more effective in bolstering herd immunity than switching to a policy that includes both sexes."