Abstracto

Efficacy of a prophylactic human papillomavirus vaccine against high-grade vulval and vaginal intraepithelial neoplasia

Jorma Paavonen

Vulval and vaginal high-grade intraepithelial neoplasias (VIN 2–3 and VaIN 2–3, respectively) precede vulval and vaginal cancers. The incidence of VIN and VaIN is increasing, and the mean age of women with these lesions is decreasing. Human papillomavirus (HPV) types 16 and18 cause the majority of these lesions in young women. The most common HPV type detected is HPV16, followed by HPV18. A combined analysis of three randomized trials among 18,174 women (aged 16–26 years) showed that a quadrivalent HPV vaccine given at day 1, months 2 and 6, was highly effective against these lesions during a mean follow-up of 3 years. The vaccine efficacy in the per-protocol analysis was 100% against VIN 2–3 or VaIN 2–3 associated with HPV16/18. In the intentionto- treat population, the vaccine efficacy was 49%. The vaccine was safe and well tolerated. Thus, prophylactic administration of quadrivalent HPV vaccine is effective in preventing high-grade VIN/VaIN, suggesting that such vaccination could result in reduced rates of HPV-related vulval and vaginal cancers. This is an important ‘bonus’ effect of the vaccine.