Fig. 2

PRIMSA diagrams for three prongs of the scoping review*. *We extracted a total of 3049 articles across all three prongs of the review. We excluded articles not primary focused on polio, those focused on “upstream” such as disease physiology and vaccine development. The main reasons for not being able to extract articles are: lack of access to full text materials for some records and language limitations with included non-English articles, e.g. Spanish and Portuguese materials