TABLE 3.

Antibody levels of confirmed cases over 12 months, geometric mean neutralizing antibody titers (GMT) and IgG antibody concentrations (GMC) in binding antibody units (BAU/ml).

			Initial follow-upa	Three months convalescent visit	Six months convalescent visit	Twelve months convalescent visit
Anti-nucleoprotein IgG	Asymptomatic cases	GMC [95% CI]	8.5 [0.88–83]	3.7 [0.27–54]	1.7 [0.11–27]	1.2 [0.06–21]
		n	4	3	3	3
	Cases with symptoms	GMC [95% CI]	7.1 [4.8–10]	3.4 [2.7–4.4]	1.1 [0.78–1.5]	0.41 [0.27–0.68]
		n	60	62	67	64
	Cases requiring hospital care	GMC [95% CI]	53 [42–66]	10 [7.5–14]	4.4 [1.9–11]	2.4 [0.92–6.1]
		n	3	4	4	4
Anti-SFL IgG	Asymptomatic cases	GMC [95% CI]	8.5 [5.1–14]	3.2 [0.92–11]	2.8 [0.46–16]	2.1 [0.17–26]
		n	4	3	3	3
	Cases with symptoms	GMC [95% CI]	6.2 [4.1–8.7]	3.9 [3–5.1]	3 [2.1–4.4]	2.3 [1.5–3.7]b
		n	60	62	67	53b
	Cases requiring hospital care	GMC [95% CI]	65 [15–290]	12 [2.3–65]	17 [6.2–44]	8.1 [2.4–26]b
		n	3	4	4	3b
Anti-RBD IgG	Asymptomatic cases	GMC [95% CI]	7.6 [3.1–19]	2.7 [0.9–7.2]	1.6 [0.36–7.2]	1.4 [0.17–13]
		n	4	3	3	3
	Cases with symptoms	GMC [95% CI]	5.2 [3.6–7.2]	2.7 [2.2–3.6]	2 [1.3–2.7]	1.4 [1–2.3]b
		n	60	62	67	53b
	Cases requiring hospital care	GMC [95% CI]	63 [34–120]	6.5 [2.2–19]	11 [5–26]	5.2 [2.7–10]b
		n	3	4	4	3b
NAb to wild-type SARS-CoV-2	Asymptomatic cases	GMT [95% CI]	83 [32–220]	13 [8.7–20]	17 [2–150]	15 [2.1–110]
		n	4	3	3	3
	Cases with symptoms	GMT [95% CI]	45 [33–60]	17 [13–22]	16 [12–22]	12 [8.4–17]b
		n	59	63	67	53b
	Cases requiring hospital care	GMT [95% CI]	370 [74–1900]	52 [20–131]	60 [20–180]	25 [9.4–69]b
		n	3	4	4	4b

SFL, full-length spike glycoprotein; RBD, receptor binding domain; CI, confidence interval.^aGMC and GMT calculations include the highest antibody level measured during the initial follow up per participant. ^bGMC and GMT calculations include only the non-vaccinated.