Is the beneficial effect of multi-cohort HPV vaccination on cervical cancer and precancerous lesions seen across all educational levels?

Human papillomavirus (HPV) vaccination, implemented in multi-cohort vaccination programs in Denmark since 2008, has led to a decrease in the incidence of cervical cancer and cervical intraepithelial neoplasia grade 3 (CIN3). However, it remains unclear if the beneficial impact of this vaccination approach applies to all educational levels. In the present study, we estimated the incidence of cervical cancer and CIN3 during 2006-2023, overall and stratified by education. Information on all cases of cervical cancer and CIN3 and on education was obtained from high-quality, nationwide registries. We calculated age-standardized and age-specific incidence rates and calculated estimated annual percentage change (EAPC) with corresponding 95% confidence intervals (CI) for the early HPV vaccination period (2006-2012) and the late HPV vaccination period (2013-2023). We observed a decrease in age-standardized incidence of cervical cancer in the late vaccination period only among women with medium or long education. Impact was particularly found among women aged 20-29 years with medium (EAPC2013-2023[medium] = -14.2, 95% CI: -15.9; -12.5) or long (EAPC2013-2023[long] = -13.9, 95% CI: -15.1; -12.7) education. For CIN3, an increase in incidence was seen in the early vaccination period followed by a significant decrease in the late vaccination period, overall and stratified by education. However, in age-specific analyses, the decrease was only seen for the youngest women. Even in a country with free-of-charge multicohort HPV vaccination programs, the beneficial impact was most apparent among women with medium or long education, suggesting that educational inequalities still exist.