Study sites included in the analysis	Start of autumn 2023 national COVID-19 vaccination campaigns	Age-specific recommendation for COVID-19 vaccination for older adults	Data source for COVID-19 vaccination information	Case definition used for recruitment of patientsb
Croatia	18 Sep 2023	65	Medical records, vaccination registry, GP interview (self-report)	EU-ILI or EU-ARI
France	2 Oct 2023	65	GP interview (self-report)	Sentinelles ARI
Germany	18 Sep 2023	60	Medical records, patient’s certificate of vaccination, GP interview (self-report)	ARI
Hungary	1 Oct 2023	60	National Immunisation Registry (83.5%), GP records, self-report	EU-ARI
Ireland	2 Oct 2023	50	Data linkage to vaccine registry	EU-ARI
The Netherlands	2 Oct 2023	60	GP interview (self-report)	EU-ILI or EU-ARI
Portugal	29 Sep 2023	60	Vaccine registry look-up by GPs	EU-ARI
Spain, national	25 Sep 2023	60	Data linkage to vaccine registry	EU-ARI
Spain, Navarre region c	16 Oct 2023	60	Data linkage to vaccine registry	EU-ILI
Sweden	7 Nov 2023	65	Data linkage to vaccine registry	EU-ARI