*2.2. Data Extraction*

Two reviewers (C.P. and J.-Y.C.) independently extracted data from the selected studies using the data extraction form developed and pilot-tested based on five randomly chosen articles to finalize the form. Discrepancies in data extraction were resolved with consensus by discussing with the third reviewer (N.C.).

The following data were extracted from the selected articles: first author, year of publication, country, vaccine, equity-relevant subgroups, existing inequities, intervention(s) and comparator(s), perspective, measurement of health and non-health benefits, model type, the inclusion of herd protection, and study findings, including cost-effectiveness and health inequity impact of vaccines.
