Table 2.

Haemagglutination inhibition antibody responses for each influenza strain and SARS-CoV-2 anti-spike binding antibody responses after vaccination (day 22; immunogenicity analysis set)

		Coadministration group (n=100)		QIV-HD alone group (n=92)		mRNA-1273 vaccine alone group (n=104)
		M or n	Ratio or % (95% CI)	M or n	Ratio or % (95% CI)	M or n	Ratio or % (95% CI)
Haemagglutination inhibition antibody responses
A/H1N1
	Post-vaccination to pre-vaccination GMT ratio	96	6·4 (4·9–8·3)	86	8·1 (6·1–10·8)	100	0·9 (0·8–0·9)
	Seroconversion rate	66	68·8 (58·5–77·8)	62	72·1 (61·4–81·2)	0	0 (0–3·6)
A/H3N2
	Post-vaccination to pre-vaccination GMT ratio	96	3·1 (2·5–3·7)	86	3·5 (2·8–4·4)	100	0·9 (0·9–1·0)
	Seroconversion rate	42	43·8 (33·6–54·3)	41	47·7 (36·8–58·7)	0	0 (0–3·6)
B/Yamagata
	Post-vaccination to pre-vaccination GMT ratio	96	1·9 (1·7–2·2)	86	2·3 (1·8–2·8)	100	1·0 (0·9–1·1)
	Seroconversion rate	17	17·7 (10·7–26·8)	18	20·9 (12·9–31·0)	1	1·0 (0–5·4)
B/Victoria
	Post-vaccination to pre-vaccination GMT ratio	96	2·3 (2·0–2·6)	86	2·4 (2·0–3·0)	100	1·1 (1·0–1·1)
	Seroconversion rate	29	30·2 (21·3–40·4)	21	24·4 (15·8–34·9)	1	1·0 (0–5·4)
SARS-CoV-2 binding antibody responses
Post-vaccination to pre-vaccination GMT ratio		96	13·7 (11·2–16·8)	86	0·9 (0·7–1·0)	102	14·2 (12·0–16·9)
≥2-times rise		94	97·9 (92·7–99·7)	3	3·5 (0·7–9·9)	100	98·0 (93·1–99·8)
≥4-times rise		89	92·7 (85·6–97·0)	2	2·3 (0·3–8·1)	97	95·1 (88·9–98·4)

GMC=geometric mean concentration. Seroconversion rate, titre <10 (1/dil) study day 1 and post-vaccination titre ≥40 (1/dil) at day 22, or titre ≥10 (1/dil) at day 1 and a ≥4-times rise in titre (1/dil) at day 22. GMT=geometric mean titre. M=number of participants with GMC or GMT data at the specified time point. n=number of participants seroconverted or with a ≥2-times or ≥4-times rise in concentration. QIV-HD=high-dose quadrivalent influenza vaccine.