. 2023 May 24. Online ahead of print. doi: 10.1016/j.cmi.2023.05.020

Table 1.

Waning of antibody titers since the last immune-conferring event (vaccination or infection) among 2- or 3-dose vaccine recipients

	Estimated spike antibody titers (AU/mL) after the last immune-conferring event, GMT (95% CI)				Slope of antibody waning, RoM (95% CI)
	Day 14	Day 30	Day 90	Day 180	Per 30 d	Comparison of slopes
2-dose	14 426 (13 692–15 199)	10 284 (9893–10 690)	3393 (3282–3509)	1034 (983–1089)	0.64 (0.63–0.65)	Reference
3-dose	24 389 (23 069–25 783) ^a	20 280 (19 450–21 146)^a	10 663 (10 317–11 021)^a	4699 (4540–4864)^a	0.75 (0.74–0.76)	1.17 (1.16–1.19)	reference
2-dose + infection	25 904 (18 164–36 942)^a	25 400 (19 323–33 388)^a	20 995 (17 000–25 928)^a^,^b	11 167 (8565–14 560)^a^,^b	0.84 (0.78–0.91)	1.32 (1.23–1.43)	1.13 (1.05–1.21)
3-dose + infection	35 131 (30 078–41 032)^a^,^b	37 543 (33 590–41 961)^a^,^b	35 119 (31 821–38 758)^a^,^b	12 476 (9986–15 586)^a^,^b	0.79 (0.75–0.83)	1.24 (1.17–1.31)	1.05 (1.01–1.11)

Shown are the estimated GMT of anti-SARS-CoV-2 spike protein antibody titers on 14, 30, 90, and 180 d since the last immune-conferring event (vaccination or infection) and the estimated RoM of antibody waning slopes, with adjustment for age (<40 or ≥40 y), sex (male or female), body mass index (<27.5 or ≥27.5 kg/m²), coexisting diseases (yes or no), immunosuppressant use (yes or no), smoking status (current or non-smoker), and frequency of alcohol drinking (<1 or ≥1 time/wk).

GMT, geometric mean titer; RoM, ratio of means.

p < 0.05 (reference is 2-dose).

p < 0.05 (reference is 3-dose).