Cervical intraepithelial neoplasia in women who had vaccination against HPV

Objective To investigate the characteristics of women developing cervical intraepithelial neoplasia who had had a vaccination against human papillomavirus (HPV). Methods A retrospective cohort study was carried out of women diagnosed with moderate or severe cervical dysplasia (CIN2+) in four Italian centers between 2015 and 2017. All women included had had previous bivalent or quadrivalent vaccination against HPV. Results The present study included 43 patients affected by CIN2+. The median age was 28 (range, 21-41) years. Ten (23.3%) patients did not have a diagnosis of specific HPV type(s) involved: high-risk HPV was detected in 7 (16.3%) women while HPV testing was negative in 3 (6.9%) women. Lesions related to HPV16 were found in two patients. HPV types covered by nonavalent vaccination were diagnosed in 27/33 (81.8%) women. HPV types not covered by nonavalent vaccination were diagnosed in 6 (18.2%) women. Co-infections are most commonly detected in women with HPVs other than those included in the nonavalent vaccination (P=0.024). Conclusion Cervical dysplasia occurring after HPV vaccination is a rare condition. Theoretically, nonavalent vaccination should improve protection against more than 80% of HPV-related lesions compared to other vaccines.