HPV vaccination programs significantly reduce human papillomavirus infections and precancerous cervical lesions, a new global review finds.

Vaccination protects against the HPV strains that cause the majority of cervical cancers.

Researchers analyzed 65 studies that included data collected over eight years from more than 60 million people in 14 high-income countries.

They found a significant decline after vaccination in the two types of HPV that cause 70% of cervical cancers -- HPV 16 and 18.

In addition, they reported an 83% decrease among 13- to 19-year-old girls and and a 66% decrease among women in their early 20s five to eight years after vaccination. There was a 54% reduction in three other types of HPV -- 31, 33 and 45 -- in teen girls.

Researchers also found significant decreases in precancerous cervical lesions, with a 51% reduction in 15- to 19-year-olds and a 31% reduction in 20- to 24-year-olds.

There were far fewer cases of genital warts, as well. Cases decreased 67% among 15- to 19-year-old girls and 48% in boys; 54% in 20- to 24-year-old women and 32% in men; and 31% in 25- to 29-year-old women.

The study was published in The Lancet journal.

"We saw that programs with multiple age cohorts [different age groups] of girls vaccinated and high vaccination coverage have greater direct impact and herd effects," study author Melanie Drolet said in a journal news release.

Drolet is a senior research associate at CHU de Quebec-Laval University Research Center in Canada.

She said the findings reinforce a new position from the World Health Organization (WHO), which recommends vaccinating multiple age cohorts of 9- to 14-year-old girls when the vaccine is introduced in a country.

"Because of our finding, we believe the WHO call for action to eliminate cervical cancer may be possible in many countries if sufficient vaccination coverage can be achieved," said study author Marc Brisson. He is a researcher at Laval University in Chemin Sainte-Foy, in Quebec.

Researchers noted there is a lack of data from low- and middle-income countries, where cervical cancer rates are much higher than in high-income countries.

At least 115 countries and territories include HPV vaccine in their immunization programs, and nearly 40 low- and middle-income countries are expected to do so by 2021.

Silvia de Sanjose, of PATH USA, wrote an editorial that accompanied the study.

It said the findings should help promote HPV vaccination worldwide in the face of such challenges as cost and competing budget priorities; inadequate supply; lack of awareness about the vaccine's effectiveness; and resistance to vaccination.

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