Table 2. Adjusted influenza vaccine effectiveness by vaccine type and patient setting against laboratory-confirmed influenza A in adults 65 years and older, Denmark, 2024/25 season up to 4 March 2025 (n = 32,943).

Patient setting	Vaccine name	Vaccine type	Cases			Controls			VE	95% CI	p value enhanced vs standard^a
Patient setting	Vaccine name	Vaccine type	All	Vacc.	%	All	Vacc.	%	VE	95% CI	p value enhanced vs standard^a
All	Efluelda Tetra	High-dose QIV	1,332	125	9.4	12,404	1,283	10.3	50	38–59	0.005
	Fluad Tetra	Adjuvanted QIV	2,685	1,478	55.1	24,840	13,719	55.2	48	42–52	< 0.0001
	Influvac Tetra/Vaxigrip Tetra	Standard-dose QIV	1,737	530	30.5	14,601	3,480	23.8	33	24–41	Ref.
Non-hospitalised	Efluelda Tetra	High-dose QIV	516	78	15.1	3,580	669	18.7	50	35–62	0.03
	Fluad Tetra	Adjuvanted QIV	1,004	566	56.4	7,157	4,246	59.3	49	40–57	< 0.0001
	Influvac Tetra/Vaxigrip Tetra	Standard-dose QIV	759	321	42.3	4,688	1,777	37.9	31	17–42	Ref.
Hospitalised	Efluelda Tetra	High-dose QIV	816	47	5.8	8,824	614	7.0	53	35–66	0.05
	Fluad Tetra	Adjuvanted QIV	1,681	912	54.3	17,683	9,473	53.6	47	41–53	0.001
	Influvac Tetra/Vaxigrip Tetra	Standard-dose QIV	978	209	21.3	9,913	1,703	17.2	36	23–47	Ref.

CI: confidence interval; QIV: quadrivalent influenza vaccine; Ref.: reference; Vacc.: vaccinated; VE: vaccine effectiveness.

^a The effectiveness of the enhanced vaccines high-dose QIV and adjuvanted QIV are compared with the effectiveness of the standard-dose QIV.