Prophylactic HPV Vaccines in Patients with HPV-associated Diseases and Cancer.

Individuals with human papillomavirus (HPV)-related disease remain at risk for subsequent HPV infection and related disease after treatment of specific lesions. Prophylactic HPV vaccines have shown benefits in preventing subsequent HPV-related disease when administered before or soon after treatment. Based on our understanding of the HPV life cycle and vaccine mechanism of action, prophylactic HPV vaccination is not expected to clear active persistent HPV infection or unresected HPV-associated dysplastic tissue remaining after surgery. However, vaccination may reasonably be expected to prevent new HPV infections caused by a different HPV type as well as re-infection with the same HPV type, whether from a new exposure to an infected partner or through autoinoculation from an adjacent or distant productively infected site. In this review, we describe the evidence for using prophylactic HPV vaccines in patients with HPV-associated disease before, during, or after treatment and discuss potential mechanisms by which individuals with HPV-associated disease may or may not benefit from prophylactic vaccines. We also consider how precise terminology relating to the use of prophylactic vaccines in this population is critical to avoid the incorrect implication that prophylactic vaccines have direct therapeutic potential, which would be counter to the vaccine's mechanism of action, as well as considered off-label. In other words, the observed effects occur through the known mechanism of action of prophylactic HPV vaccines, namely by preventing virus of the same or a different HPV type from infecting the patient after the procedure.