Human Papillomavirus, HPV, vaccination significantly reduced the incidence of cancerous/precancerous condition of the genital tract. The quadrivalent vaccine type 6,11,16,18 was licensed in 2006; more recently, the Food and Drugs Administration (FDA) approved the nonavalent vaccination against HPV. Here, we aimed to test the theoretical utility of the incorporation of nonavalent vaccination into a clinical setting.
Data of consecutive patients undergoing sampling for HPV DNA testing from 1998 to 2015 were retrospectively searched in order to identify changes in HPV prevalence during three study periods (T1, 1998-2003; T2, 2004-2009; and T3, 2010- 2015).
We enrolled 13,665 patients: 1361, 5130, 7174 patients, in T1, T2 and T3, respectively. Potentially, the quadrivalent vaccine protected against HPV infection in 71.5%, 46.5% and 26.5% of patients tested in T1, T2 and T3, respectively (p-fortrend<. 001). While, the nonavalent vaccine protected against HPV infection in 92.5%, 72.3% and 58.1% of patients tested in T1, T2 and T3, respectively (p-for-trend<.001). The proportion of patients with genital dysplasia grade2+, not related to HPV genotypes covered by quadrivalent vaccine (13% in T1, 21% in T2 and 34% in T3) and nonavalent vaccine (3% in T1, 12% in T2 and 19% in T3) increased over the time (p-for-trend<.001). For all study period the nonavalent vaccine was superior that quadrivalent vaccine in protect against HPV infection (p<.001).
Our data suggested that potentially the introduction of the nonavalent vaccine would improve protection against HPV infections and HPV-related genital dysplasia2+. Moreover, we can speculate that cross protection of nonavalent vaccine will be related to a highest coverage against other HPV types.