Women previously vaccinated against human papillomavirus (HPV) type 16 and 18 are now reaching the age (21 years) at which cervical-cancer screening is recommended in the U.S. The impact of HPV vaccination on risks of cervical precancer following a positive and negative screen among women aged 21-24 years who just started routine cervical screening are not well described. Therefore, three-year absolute and relative (RR) cumulative risks of cervical intraepithelial neoplasia grade 2 or more severe diagnoses (≥CIN2) and grade 3 or more severe diagnoses (≥CIN3) were estimated for women undergoing cervical screening at Kaiser Permanente Northern California. Risks were estimated in women aged 21-24 years (n = 75,008) undergoing cervical screening since late 2006, 6 months after HPV vaccination became available; women were categorized vaccinated at ages <18, 18-20, and 21-24 years and compared to those who were unvaccinated. Three-year risks were estimated for normal, low-grade, and high-grade cytology results. Three-year risks of ≥CIN2 and ≥CIN3 for unvaccinated women following low-grade cytology were 10.89% for and 3.70%, respectively. By comparison, Three-year risks of ≥CIN2 and ≥CIN3 were 5.26% (RR = 0.48, 95%CI = 0.24-0.99) and 0.99% (RR = 0.27, 95%CI = 0.06-1.13), respectively, for women vaccinated under the age of 18 years. Three-year ≥CIN2 and ≥CIN3 risks were lower for those HPV vaccinated at younger age for any screening result (ptrend ≤ 0.01 for all comparisons). These data support initiating cervical screening at an older age or changing the management of a low-grade cytology result in women aged 21-24 years who were vaccinated against HPV younger than age of 18 years.
Keywords: Cervical precancer; Cytology; Human papillomavirus (HPV); Screening; Vaccination.
Copyright © 2018. Published by Elsevier Inc.