Table 2

Characteristics of included studies

Study	Location and year of the study	Response rate (%)	Study sample (n)	Provision of the vaccine	Type of secondary care	Predictors per study
Study	Location and year of the study	Response rate (%)	Study sample (n)	Provision of the vaccine	Type of secondary care	Demographic	Behavioural	Organisational
Al-Tawfiq et al15	Multi-national,^* 2007	54.2	450	Unknown	Hospital	x	x	x
Beguin et al16	Belgium, 1996	37.2	4109	Free of charge to HCWs who wished to be vaccinated	UMC^†	x	x
Bull et al 24	Australia, 2005	69.7	63 330	Coordinated by the infection control department during autumn	Hospital	x
Christian17	USA, 1990	63.3	379	Offered to all employees annually, $2 administration fee	Hospital	x	x
Christini et al18	USA, 2005	42.2	2467	Free of charge, through advertised clinics and mobile carts, fact sheet provided	UMC^†	x
Lester et al19	Canada, 2000	58.0	1195	Unknown	UMC^†	x
Maltezou et al20	Greece, 2006	8.9	8062	Unknown	Public hospital	x	x
Nichol et al21	USA, 1994	38.0	1031	Annual influenza vaccination program, walk-in clinic, mobile carts	UMC^†	x	x
Piccirillo et al22	USA, 2004	87.0	230	Unknown	Community hospital	x	x	x
Saluja et al23	Canada, 2000	80.5	426	Unknown	UMC^† emergency departments	x	x
Steiner et al10	USA, 1999	84.2	2200	Free influenza vaccination offered during mandatory tuberculosis screening of all employees	Tertiary care hospital	x	x
Tapiainen et al25	Switzerland, 2004	75.5	538	Free of charge for all HCWs	University children's hospital	x
Weingarten et al9	USA, 1987	41.1	463	Available to hospital employees at a $5 charge	Acute care UMC^†	x

Total			84 880			13	8	2
Average (95% CI)		56.9 (43.1 to 70.7)

↵* Multi-nationality survey among HCWs from the UK, USA, South Africa and Saudi Arabia.
↵† UMC (university medical centre) indicates a university medical hospital or teaching hospital.
HCW, healthcare worker.