Implementing WHO Guidance on Conducting and Analysing Vaccination Coverage Cluster Surveys: Two Examples from Nigeria

In 2015, the World Health Organization substantially revised its guidance for vaccination coverage cluster surveys (revisions were finalized in 2018) and has since developed a set of accompanying resources, including definitions for standardized coverage indicators and software to calculate them. In addition to tabular presentations of coverage by vaccine and age group, the guidance document and software (named the Vaccination Coverage Quality Indicators - VCQI) – provide insight into crude coverage versus valid doses, vaccination timeliness, missed opportunities for simultaneous vaccination, and vaccination campaign coverage stratified by several parameters, including the number of previous doses received. The VCQI software furnishes several helpful ways to visualize survey results. The current WHO survey guidance was used to design and conduct two nationally representative vaccination coverage surveys in Nigeria – one to assess routine immunization and one to measure post campaign coverage. The primary analysis for both surveys was conducted using VCQI. This paper describes those surveys and highlights some of the analyses that are facilitated by the new resources.