Vaccination programs against the human papillomavirus (HPV) have substantially reduced the number of infections and cervical precancerous lesions caused by the virus, according to a study published in 'The Lancet' by researchers from the Université Laval and the Québec CHU Research Center-Université Laval, in Canada. The results are so promising that it is now possible to foresee the elimination of cervical cancer as a public health problem in the coming decades.
Certain forms of the virus can cause anogenital warts, while others cause lesions that can develop into cancers of the mouth, throat, vagina, vulva, anus or penis, and particularly in the cervix. “HPV is found in almost 100 percent of cervical cancer cases,” says lead author Mélanie Drolet.
The research team led by Professor Marc Brisson, from the Faculty of Medicine of Laval University, conducted a meta-analysis of 65 studies in 14 different countries that have established HPV vaccine programs in the last ten years. Using data from 60 million people, the researchers compared the frequency of HPV infections, anogenital warts, and precancerous cervical lesions before and after the programs were launched.
Their analysis shows that infections decreased by 83 percent among girls aged 13 to 19 and by 66 percent among women aged 20 to 24. For anogenital warts, the decrease was 67 percent among girls aged 15 to 19, 54 percent for older women. 20 to 24, and 31 percent for those between 25 and 29 years old. Precancerous cervical lesions also decreased by 51 percent among adolescents aged 15 to 19 years and 31 percent among women aged 20 to 24 years.
The vaccination of young women is also producing herd protection for young men. Anogenital warts among men have decreased by 48 percent for those aged 15 to 19 and by 32 percent for those aged 20 to 24 years.
“Vaccination against HPV is still too recent to directly measure its effects on cervical cancer, since it can take decades to develop,” says Mélanie Drolet. But our analyzes show that vaccination is producing substantial reductions in infections that cause cervical cancer and precancerous lesions. “
“These reductions are a first sign that vaccination could eventually lead to the elimination of cervical cancer as a public health problem. Now we are trying to determine when the elimination could be achieved and which vaccination and detection programs could help us achieve it faster, “he concludes.