The Big Catch-up (BCU) is a global strategy to close the immunization gaps caused by backsliding of immunization coverage during the COVID-19 pandemic. This BCU case study methodology aims to facilitate an in-depth understanding of a country’s catch-up planning, implementation, and results to bring out lessons learned and evidence for next steps. 

A BCU case study aims to understand:

• How has the country team planned, implemented, and monitored catch-up vaccination of children >2 years of age who have missed one or more doses of nationally recommended vaccines?
• How can identifying and catching up children who have missed routine vaccines be established, strengthened, and institutionalized as part of immunization services and PHC to sustainably reach those missed?
• Why are there individuals who are still not reached with vaccination through either on time vaccination or catch-up?

This guidance includes a Case Study Protocol Template, and Data Collection Tools that can be adpated as needed by country teams.