Feasibility of Quadrivalent HPV Vaccination as Immunologic Booster to Prevent Relapses In an Italian Cohort of Women Treated for Cervical Intraepithelial Neoplasia (CIN)

To date it’s clear that the HPV (Human Papilloma Virus) vaccine is most effective in women when administered before first sexual intercourse with reduced benefit in those who are already HPV positive; for this reason World HPV vaccination programs are provided before the mean age of sexual debut [1,2]. HPV vaccines have been approved for safe administration from 9 years of age up to 45. In particular, studies have focused on children and adolescents aged 9-15 years for the increased activity of immune system at this age and for the higher probability that subjects result still naïve to the virus [3]. In Italy, the free offer of vaccination is directed to all teenagers from 12 years of age and the right to free vaccination is up to the limit of 18 years for the start of vaccination series. Vaccination before the start of sexual intercourse is particularly advantageous, because it induces effective protection before a possible virus infection, which is usually acquired soon after the onset of sexual activity, and because the immune response is greater in this age group than that observed in older women [3]. The unclear matter is whether the vaccine has any impact on existing HPV infections and any benefit in women who have been previously treated for pre-invasive cervical diseases [1,2]. Most of available clinical data have demonstrated an absence of benefit in women who are HPV positive for the types contained in the vaccine and that HPV vaccines have not a therapeutic efficacy [1]. However, preliminary studies applied in different realities from countries except Italy have shown that HPV vaccine can also induce protection in older women, and especially the administration of vaccine in patients previously treated for HPV-related disease can reduce the recurrence rate of disease [4-6]. Recent studies have shown that the vaccine could be able to stimulate the immune response in women of older age and to protect against HPV although the probability of having already been infected is high [4-6]. Vaccination is now possible up to 45 years as a personal preventive tool, at the expense of the patient, as indicated in the data-sheet of the quadrivalent vaccine currently available on the market. In fact, the vaccine is also safe at this age, is well tolerated and is able to determine an antibody response, as demonstrated in many studies [7,8]. From available data in literature and in our experience, it is estimated that recurrence rate of HPV-related disease is about 30-35% for genital warts and about 10-15% for pre-invasive disease three years after the initial surgery [5]. As mentioned above, Australia tried to expand vaccination coverage by administering HPV vaccine even in women who had already contracted the virus. Collected data regarding the efficacy of HPV vaccination in reducing the recurrence rate of HPV-related disease were very satisfactory. Results have shown that the vaccine is able to reduce the risk of recurrence of pre-neoplastic pathologies and genital warts in women already treated for HPV-related diseases [4,5].