Table 3. The influence of age to GMT and Seropositivity.

Time point	Statistic	Total	18–44 years	45–64 years	≥65 years	p
Pre-V	GMT	2.1	2.2	2.1	2.1	0.908
	95% CI	2.0–2.2	1.9–2.4	1.9–2.4	2.0–2.3
	Seropositivity (%)	3.3	3.6	4.8	2.4
V2-1m	GMT	29.4	33.2	36.8	24.3	0.019
	95% CI	23.5–24.2	25.3–43.4	24.3–55.7	20.0–29.5
	Seropositivity (%)	98.9	100	95.2	100
V2-3m	GMT	15.5	22.9	16.0	11.5	<0.01
	95% CI	13.3–18.0	17.0–30.9	12.5–20.5	9.4–14.2
	Seropositivity (%)	95.5	100	95.2	92.7
V2-6m	GMT	6.6	10.2	7.9	4.4	<0.01
	95% CI	5.4–8.0	7.0–14.7	5.1–12.3	3.5–5.7
	Seropositivity (%)	57.8	82.1	66.7	35.6
V3-1m	GMT	168.2	217.2	152.3	148.7	0.369
	95% CI	139.7–202.6	165.7–287.7	97.3–238.5	110.7–199.7
	Seropositivity (%)	100.0	100	100	100

The seropositivity rate is when positive NT50 is above 1:4.

GMT, geometric mean titers.