A team of Scottish researchers have been able to give the assurance that routine vaccination of young girls aged 12 to 13 years with human papillomavirus (HPV) vaccine results in a reduction in pre-invasive cervical disease in a study just published online in The BMJ.
Tim Palmer, Ph.D., from the University of Edinburgh in the United Kingdom, and colleagues conducted a retrospective population study involving 138,692 women born between Jan. 1, 1988, and June 5, 1996, who had a smear test result recorded at age 20.
The researchers found that vaccinated women born in 1995 and 1996 had an 89 percent reduction in prevalent cervical intraepithelial neoplasia (CIN) grade 3 or worse (from 0.59 to 0.06 percent), an 88 percent reduction in CIN grade 2 or worse (from 1.44 to 0.17 percent), and a 79 percent reduction in CIN grade 1 (from 0.69 to 0.15 percent) compared with unvaccinated women born in 1988.
There was a correlation between younger age at immunization and increasing vaccine effectiveness: 86 versus 51 percent for CIN grade 3 or worse for women vaccinated at age 12 to 13 years versus those vaccinated at age 15 years. In unvaccinated girls in the 1995 and 1996 cohorts, there was evidence of herd protection against high-grade cervical disease.
“The reduction in disease in routinely immunized women, who will form the bulk of the screened population in years to come, mandates revision of screening and referral guidelines,” the authors wrote.
REFERENCE: Palmer et al: Prevalence of cervical disease at age 20 after immunisation with bivalent HPV vaccine at age 12-13 in Scotland: retrospective population study; https://www.bmj.com/content/365/bmj.l1161