Vaccines against the human papillomavirus have sharply reduced infections, genital and anal warts, and precancerous lesions in young women and girls in more than a dozen wealthy countries, a major new study has found — powerful evidence that these vaccines will ultimately cause major drops in cervical cancer.

The vaccines are so effective that when given to enough young girls, they also give partial protection to both unvaccinated girls and boys, simply because fewer people in sexual networks are carrying the virus, commonly called HPV.

The research, published on Thursday in the Lancet, analyzed dozens of studies that, when combined, included 66 million females and males below the age of 30 living in 14 wealthy countries where HPV vaccines were introduced as early as 2007.

The World Health Organization’s calls to eliminate cervical cancer “may be possible in many countries if sufficient vaccination coverage can be achieved,” said Marc Brisson , a biostatistician at Laval University in Quebec and one of the study’s authors.