Monitoring the impact of HPV vaccine in males-Considerations and challenges.

In this article, we examine the issues involved if national or sub-national programs are considering extending post HPV vaccine introduction monitoring to include males. Vaccination programs are now being extended to include males in some countries, in order to improve population level HPV infection control and to directly prevent HPV-related disease in males such as anogenital warts and anal cancers. Coverage and adverse events surveillance are essential components of post-vaccination monitoring. Monitoring the impact of vaccination on HPV infection and disease in men raises some similar challenges to monitoring in females, such as the long time frame until cancer outcomes, and also different ones given that genital specimens suitable for monitoring HPV prevalence are not routinely collected for other diagnostic or screening purposes in males. Thus, dedicated surveillance strategies must be designed; the framework of these may be country-specific, dependent upon the male population that is offered vaccination, the health care infrastructure and existing models of disease surveillance such as STI networks. The primary objective of any male HPV surveillance program will be to document changes in the prevalence of HPV infection and disease due to vaccine targeted HPV types occurring post vaccination. The full spectrum of outcomes to be considered for inclusion in any surveillance plan includes HPV prevalence monitoring, anogenital warts, potentially pre-cancerous lesions such as anal squamous intraepithelial lesions (SIL), and cancers. Ideally, a combination of short term and long term outcome measures would be included. Surveillance over time in specific targeted populations of men who have sex with men and HIV-infected men (populations at high risk for HPV infection and associated disease) could be an efficient use of resources to demonstrate impact.