Young women who received human papillomavirus (HPV) vaccines as adolescents had significantly lower rates of a condition that’s a precursor to cervical cancer, in a nationwide study in Scotland.
“The magnitude of the effect is greater than expected,” study author Dr. Tim Palmer from the University of Edinburgh told Reuters Health by email.
Receiving three doses of the vaccine at the recommended ages of 12 to 13 was associated with “a profound reduction of cervical disease seven years later,” he and his colleagues report in the BMJ.
One of the most common sexually transmitted diseases, HPV doesn’t cause symptoms and usually goes away on its own. But the virus can cause cancer of the cervix, the fourth most common cancer in women, as well as cancers of the throat and penis.
Study findings
Palmer’s team studied 138,692 women, about half of whom had been fully vaccinated against HPV either at ages 12-13, or later in their teens. At age 20, the women all had tests to look for abnormal cells on the cervix — called cervical intraepithelial neoplasia, or CIN — that can lead to cancer.
Rates of CIN were low overall. But compared with unvaccinated women, vaccinated women had:
- An 89 per cent lower rate of CIN Grade 3 or worse (0.59 per cent in unvaccinated women versus 0.06 per cent in the vaccinated group).
- An 88 per cent lower rate of CIN Grade 2 or worse (1.44 per cent versus 0.17 per cent).
- A 79 per cent lower rate of CIN Grade 1 (0.69 per cent versus 0.15 per cent).
Grades 2 and 3 are usually treated with surgery.
Girls who were vaccinated at ages 12-13 got a greater benefit: the vaccine was 86 per cent effective for them, and 51 per cent effective when given at age 17.
“The findings are dramatic and document a considerable reduction in high-Grade cervical disease over time,” Julia Brotherton, medical director