Sustained impact of bivalent <scp>HPV</scp> immunisation on <scp>CIN</scp> incidence over two rounds of cervical screening

Vaccination against high-risk HPV has been shown to reduce significantly the incidence of pre-invasive and invasive cervical disease. Clinical trials show immunity and vaccine effectiveness for over 12 years but real-life longitudinal data are lacking. Vaccination with the bivalent vaccine (3 dose schedule) for women aged 12-18 years began in Scotland in 2008; immunised women entered screening in 2010. Women immunised at age12-13 years entered screening in 2015. Linked data from ≤12 years of routine screening activity shows adjusted VE against CIN2+ at age 12-13 of 72·6% (95%CI: 67.7-76.8) and at age 14-16 of 63·2 (CI 60·4-65·8), and against CIN3+ of 81·7 (CI 76·2-78·6; age 12-13) and 68·1 (CI 64·1-71·6; age 14-16) after 3 doses or two doses 5 months apart. Adjusted VE following two doses 1 month apart or one dose only at age14 was 20.5 (95%CI: 6.1-32.6) for CIN2+ and 34.9 (95%CI:17.0-48.9) for CIN3+. No benefit was seen with vaccination over the age of 18 years. The most deprived women showed the highest incidence of CIN2+ and CIN3+, and the greatest reduction in CIN2+ and CIN3+ following complete immunisation. Herd protection is seen in all immunised cohorts. This population based analysis confirms the long-term effectiveness of the bivalent HPV vaccine, greatest in women from the most deprived areas and reinforces the importance of ensuring high vaccine uptake rates at an early age.