Fig. 3
Share of people with booster vaccinated in the three countries. Note1: The data were selected for the period from the start of COVID-19 vaccination in each of the three countries until 1 June 2023. Note2: The source of the data is the official websites of the national ministries of health of Germany, Denmark and Bulgaria. The data source for Germany is https://impfdashboard.de/en/ (accessed on 1 June 2023). The data source of Denmark is https://www.sst.dk/en/english/corona-eng/vaccination-against-covid-19 (accessed on 1 June 2023). The data source of Bulgaria is https://coronavirus.bg/bg/statistika (accessed on 1 June 2023)