Predicting optimal impact interventions in the post-HPV vaccination world.

Prophylactic vaccination is a powerful tool that changes exposure to infections and associated morbidity of preventable diseases. We discuss the impact of pneumococci and human papillomavirus (HPV) vaccination on the population biology of the two micro-organisms and related public health effects. Data on HPV type-replacement in communities where vaccine-covered HPVs are almost eliminated, and interactions of the remaining HPV types on the risk of cervical cancer are reviewed. Results of comprehensive models for European country-specific conduction of cervical screening among HPV-vaccinated and unvaccinated women, assuming different HPV-vaccination coverage and strategies, are discussed in our policy-oriented review. An acceptable balance of benefits and harms of cervical cancer screening in HPV vaccinated populations requires an understanding of cancer risks in differently vaccinated birth cohorts. Finally, the challenges are complex but can be met if strategies are applied that (i) as fast as possible achieve herd effect and (ii) use a risk-based design of HPV screening.