Cervical Cancer: Why Age of HPV Vaccination Matters ?

The human papillomavirus (HPV) vaccine is recommended up to age 14, but can be given as a catch-up vaccine up to age 19. However, its effectiveness in preventing precancerous lesions and cervical cancer decreases after this age.

The human papillomavirus (HPV) vaccine is recommended up to age 14, but can be given as a catch-up vaccine up to age 19. However, its effectiveness against precancerous lesions and cervical cancer is then reduced.

Human papillomavirus infections are among the most common sexually transmitted infections. Approximately 80% of the population is exposed to HPV during their lifetime and the majority of infections occur in the first years of sexual activity. High-risk oncogenic HPVs are responsible for precancerous lesions in the cervix, vulva, vagina, anus and cancers of the cervix, ENT, anus, penis, vulva and vagina. It is therefore recommended that all young people, girls and boys, aged 11 to 14 be vaccinated (two-dose vaccination schedule). As a catch-up, a 3-injection vaccination is recommended for young people aged 15 to 19, and even up to 26 years specifically for men who have sex with men.

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The HPV vaccine (Gardasil 9) is based on proteins that mimic the envelope of the virus but do not infect the vaccinated person. It induces extremely effective immunogenicity against the virus. “Its primary effectiveness lies in preventing chronic infection with HPV targeted by the vaccine. Remember that chronic infection is the primary risk factor for cervical cancer and other HPV-induced cancers. With vaccination, the risk of chronic infections with HPV 16 and 19 (highly oncogenic HPV, editor's note) is reduced by more than 99%”, declared Professor Xavier Carcopino, obstetrician-gynecologist, during a press conference of the French Society of Colposcopy and Cervico-Vaginal Pathology.

A reduced effectiveness of the vaccine after 14 years

But the age of vaccination plays a major role in this effectiveness. Thus, according to a Swedish study published in 2020 in The New England Journal of Medicine, vaccination before the age of 17 reduces the risk of cervical cancer by 88%. After the age of 17, by only 53%.

A second study, this one British and published in 2021 in The Lancet, shows that vaccination prevents 97% of precancerous lesions if it takes place between the ages of 12 and 13, 75% if it takes place between the ages of 14 and 16, and finally 39% if it is carried out between the ages of 16 and 18. According to the same study, cancers are reduced by 87% when vaccination is carried out before the age of 14, 62% before the age of 17, 34% before the age of 19.

In addition to the benefits of precancerous lesions are diagnosed. Cervical cancer is somewhat forgotten by the general public because it has declined due to screening, underlines Professor Carcopino, but precancerous lesions are extremely frequent. And for the 30,000 women treated each year, it is an ordeal. This involves treatment that will affect the most intimate aspects, sexuality, fertility problems, with a risk for pregnancies.” As a reminder, precancerous lesions are mainly treated by surgery, with conization (resection of the affected mucosa).

Vaccination of girls is essential, that of boys is essential

Vaccination before the age of 14 and that during the catch-up between the ages of 15 and 19 are not equal. Catch-up vaccination, up to the age of 19, will not have the same effectiveness on the occurrence of lesions and the onset of cancers.

As a reminder, the HPV vaccination campaign, the second of which began at the start of the school year in September 2024, concerns 5th grade students. If vaccination of girls is essential, that of boys is also indispensable. “Vaccinating boys against HPV will, subject to sufficient vaccination coverage, slow transmission within the general population, and thus better protect boys and men, but also better protect unvaccinated girls and women”, underlines the National Cancer Institute.