Early Benefits for Quadrivalent HPV Vaccine in Canadian Teens
Reduced incidence of dysplasia and anogenital warts among girls vaccinated in grades 8 to 9
MONDAY, April 27, 2015 (HealthDay News) -- Quadrivalent human papillomavirus (qHPV) vaccination for young girls is associated with reduced incidence of dysplasia and anogenital warts (AGW), according to a study published online April 27 in Pediatrics.
Leah M. Smith, from McGill University in Montreal, and colleagues examined the impact of the qHPV vaccine and Ontario's grade 8 qHPV vaccination program on cervical dysplasia and AGW. A population-based retrospective cohort of girls in grade 8 before and after program implementation was identified. The authors ascertained vaccine exposure in grades 8 to 9 and outcomes in grades 10 to 12. The cohort included 131,781 ineligible and 128,712 eligible girls.
The researchers identified 2,436 and 400 cases of dysplasia and AGW, respectively. Vaccination correlated with a significant reduction in the incidence of dysplasia by 5.70 per 1,000 girls, a relative reduction of 44 percent (relative risk [RR], 0.56; 95 percent confidence interval [CI], 0.36 to 0.87). A significant protective effect on dysplasia was seen for program eligibility (absolute risk difference [RD], −2.32 per 1,000; RR, 0.79; 95 percent CI, 0.66 to 0.94). Reductions in AGW were due to vaccination (RD, −0.83 per 1,000; RR, 0.57; 95 percent CI, 0.20 to 1.58) and program eligibility (RD, −0.34 per 1,000; RR, 0.81; 95 percent CI, 0.52 to 1.25).
"This study provides strong evidence of the early benefits of qHPV vaccination among girls aged 14 to 17 years, offering additional justification for not delaying vaccination," the authors write.