Association between sex hormones and anti-S/RBD antibody responses to COVID-19 vaccines in healthcare workers

Figures & data

Table 1. Demographic characteristics of the study population.

	Study population	Males	Females
	n = 521	137 (26.3%)	384 (73.7%)
median age	43	45	41
IQR; range	(31–52); (22–81)	(34–55); (24–66)	(30–51); (22–81)
age groups
20–44 years	282 (54.2%)	63 (46.0%)	219 (57.0%)
45–55 years	157 (3.1%)	43 (31.4%)	114 (29.7%)
56–85 years	82 (15.7%)	31 (22.6%)	51 (13.3%)

IQR: interquartile range.

Table 2. Geometric means and 95%CI of anti-S/RBD levels (AU/mL) at the three considered time points after second dose of vaccine; p-values refer to the comparison among groups at each measurement.

	I measurement	II measurement	III measurement
days since second vaccination
median (IQR); (range)	16 (15–17); (12–37)	77 (76–78); (34–101)	154 (151–156); (122–243)
	Geometric mean and (95% CI) of anti-S/RBD levels (AU/mL)
all individuals	2,169 (2,040–2,306)	539 (506–574)	179 (167–191)
males	1,640 (1,447–1,857)	421 (372–476)	149 (132–170)
females	2,397 (2,240–2,565)	588 (548–632)	191 (177–206)
p-values males vs females	<.001	<.001	<.001
Age groups
20–44	2,407 (2,234–2,595)	599 (553–649)	205 (189–223)
45–55	2,034 (1,824–2,267)	493 (439–552)	159 (142–179)
56–85	1,714 (1,403–2,094)	444 (370–533)	139 (114–171)
p-values for age groups	.002	.002	<.001
males aged
20–44	1,822 (1,528–2,171)	495 (414–593)	183 (152–219)
45–55	1,635 (1,532–1,978)	387 (317–473)	134 (109–168)
56–85	1,329 (944–1,869)	340 (254–456)	114 (85–152)
p-values for age groups	.166	.015	.008
females aged
20–44	2,609 (2,409–2,825)	634 (579–691)	212 (193–233)
45–55	2,208 (1,939–2,515)	539 (471–618)	169 (148–194)
56–85	2,001 (1,566–2,558)	522 (415–656)	158 (120–208)
p-values for age groups	.037	.121	.010

Figure 1. Measurements of anti-S/receptor binding domain (RBD) (by natural log transformed values and 95%CI) in the groups classified based on sex and age: (a) overall; (b) 20–44 years; (c) 45–55 years and (d) 56–85 years; p-values by Wilcoxon – Mann–Whitney test are shown for each post-vaccination time point.

Figure 2. Analysis of sex differences in anti-S/RBD waning. Scatters for the log values of anti-S/RBD antibody levels with the regression lines estimated using mixed regression model for males (M) and females (F), panel (a) all age groups; panel (b) 20–44 years; panel (c) 45–55 years; panel (d) 56–85 years; p-values relative to anti-S/RBD antibody slope differences in M vs F are shown in each panel.

Figure 3. The effect of sex hormones on the anti-S/RBD response to vaccination. Simple regression models for anti-S/RBD antibody levels applied in a subgroup of healthcare workers (HCWs, n = 112) using the log of sex hormone plasma levels as a covariate; 17-β estradiol: a (females) and B (males); testosterone: C (females) and D (males); progesterone: E (females) and F (males); beta estimates (slopes) with relative p-values obtained using regression models are shown in each panel.