In most countries, human papillomavirus (HPV) vaccination uptake in girls is relatively low, and, together with the limited target age range, this has led to HPV transmission control not reaching its full potential. The multinational VIVIANE study showed that the bivalent HPV vaccine is efficacious in adult women. Integrating adult HPV vaccination into existing public health programs could therefore be an effective strategy to improve HPV and cervical cancer prevention. The objective of our study was to estimate the impact of adding adult HPV vaccination to the current HPV vaccination program in the Netherlands.
We used the established STDSIM microsimulation model to evaluate the following adult vaccination strategies for only adult women or both men and women, in addition to the current girls-only vaccination program: a one-time mass campaign for the 24-45 year age group, vaccination at the first cervical cancer screening visit for 30-year old women, vaccination at sexual health clinics for the 15-29 year age group, and combinations of these strategies. Outcome measures were incremental incidence reductions of HPV-16 and HPV-18 and incremental number needed to vaccinate (NNV) to prevent an HPV-16/18 infection, both compared to the current Dutch vaccination program.
The estimated impact of extending vaccination to adult women is modest, with largest incremental HPV incidence reductions occurring when offering vaccination both at the first cervical cancer screening visit and at sexual health clinics (i.e. about 20% lower after 50 years for both HPV-16 and HPV-18). The largest incidence reduction was achieved by adding male vaccination at sexual health clinics to this strategy (63% for HPV-16 and 84% for HPV-18). For this strategy, the incremental NNV to prevent one infection in women is 5.48, compared to 0.90 for the current vaccination program.
Extending HPV vaccination to adult women and men would substantially reduce HPV incidence in the Netherlands. Since existing infrastructures can be used, HPV vaccination for adults, especially at the first cervical cancer screening visit (for women) and at sexual health clinics (both sexes), would be an important and highly efficient policy measure to further improve HPV prevention and subsequently avert cervical and other HPV-related cancers, both in men and women.