Cohort study of association of quadrivalent human papillomavirus vaccine with high-grade vulvovaginal lesions

HPV vaccination has been associated with reduced risk of high-grade cervical lesions; however, evidence on its association with high-grade vulvovaginal lesions is scarce. A cohort study in Sweden investigated this association. Among 778,943 women born between 1985 and 1998 and residing in Sweden between 2006 and 2022, a total of 256,353 (32.9%) received at least one dose of the quadrivalent HPV vaccine. The median (IQR) follow-up duration was 17.0 (17.0-17.0) years for unvaccinated women, 12.2 (10.6-13.4) years for those vaccinated between ages 10 and 16 years, and 10.8 (9.3-13.5) for those vaccinated at 17 years or older. During follow-up, 98 cases of high-grade vulvovaginal lesions were found in vaccinated women and 547 cases were found in unvaccinated women. Compared with unvaccinated women, the fully adjusted incidence rate ratio of high-grade vulvovaginal lesions was 0.63 (95% CI 0.50-0.81) in vaccinated women; stratified by age at vaccination, the IRRs were 0.45 (0.32-0.65) for those vaccinated at age 10 to 16 years and 0.80 (0.61-1.06) for those vaccinated ag age 17 years or older. The authors conclude that quadrivalent HPV vaccination was associated with reduced risk of high-grade vulvovaginal lesions, suggesting that expanding vaccination, especially at younger ages, could help prevent high-grade vulvovaginal lesions.