Monitoring for coverage, effectiveness, impact, usage (loss and wastage), and safety of vaccines should be planned and use existing systems as much as possible. Collection of coverage data can be challenging, and should include disaggregated data by dose and age at delivery site. Nominal registries may be useful for collecting coverage information and ensuring proper follow-up, but may require unique national identifiers. With appropriate technical support, vaccine impact evaluations may be done using HPV prevalence studies in certain settings. WHO recommends that all countries establish or enhance cancer registries to be able to evaluate the impact of cervical cancer prevention.
