Unlike cervical HPV-associated conditions, those of the anal region are increasing in all jurisdictions studied. Furthermore, treatment of anal high grade squamous intraepithelial lesions (HSIL) may be associated with considerable morbidity and high rates of recurrence.
Prevention of anal HPV infection and related conditions is currently dependent on the administration of prophylactic vaccination to individuals, ideally before the onset of sexual activity. There are currently three options: bivalent (bHPV- targeting HPV 16 and 18), quadrivalent (qHPV - targeting HPV 6,11,16 & 18) and nonavalent (nHPV - targeting HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58) vaccines.
Much of the research on the efficacy, safety and immunogenicity of these vaccines has been done in the context of cervical disease. However, there are significant differences between the natural history of cervical and anal HPV infection. Much less is known about how anal HPV-related conditions behave in the context of both genders, men who have sex with men, and the immunosuppressed.
There has been only one published large-scale phase randomised controlled trial of the efficacy of prophylactic HPV vaccines in preventing anal HPV-related disease. In this, the rates of grade 2 or 3 anal intraepithelial neoplasia related to infection with HPV-6, 11, 16, or 18 were reduced by 54.2% in the intention-to-treat population and by 74.9% in the per-protocol efficacy population. Persistent anal infection with HPV-6, 11, 16, or 18 infections were reduced by similar amounts.
This presentation will review relevant data from other, related, studies and assess what we can infer regarding the use of prophylactic HPV vaccination in the context of prevention of anal HPV-related disease in other populations.
It will conclude with a review of clinical scenarios where vaccination to prevent anal HPV infection may be considered outside existing programs.