**2. Materials and Methods**

#### *2.1. Data Sources*

All HSS proposals submitted by Gavi-supported countries from 2014 to 2021 inclusively were reviewed. The overall number of Gavi-supported countries during this period varied from 73 in 2014 to 57 in 2021 [5]. These proposals were most likely to have been developed and/or implemented during the Gavi 4.0 strategy period (2016–2020). Older proposals were excluded because they were written well before Gavi 4.0 and thus would likely not be focused on increasing equity. Two countries submitted two different HSS proposals during this period. In these cases, we included only the oldest one since 2014 in the analysis as those were more likely to have followed Gavi 4.0 recommendations and to have been implemented during that period. The documents were available through the "country documents" web pages on the Gavi website [18]. The final mapping included 56 HSS proposals from 55 countries (with two separate proposals for Syria related to different regions).
