Table 1.

Donor sample population demographics and SARS-CoV-2 antibody detection.

Study Variable			Total	Donors with SARS-CoV-2 antibody detected	Crude seroprevalence(% [95%CI])	Adjusted seroprevalence*(% [95%CI])	p-value
Donor population			8509	187	2.20% [1.89 – 2.54]	2.41% [2.09 – 2.76]
Month	February		1047	2	0.19% [0.02 – 0.69]
	March		1033	3	0.29% [0.06 – 0.85]
	April		1342	39	2.91% [2.07 – 3.97]		<0.0001
	May		1277	37	2.90% [2.04 – 3.99]
	June		1365	37	2.71% [1.91 – 3.74]
	July		1116	29	2.60% [1.74 – 3.73]
	August		663	23	3.47% [2.20 – 5.21]
	September		666	17	2.55% [1.49 – 4.09]
Gender	Male		4842	104	2.15% [1.76 – 2.60]	1.86% [1.50 – 2.29]
	Female		3667	83	2.26% [1.80 – 2.81]	2.43% [1.97 – 2.96]
Age (yrs)	18–29		1133	46	4.06% [2.97 – 5.42]	5.30% [4.04 – 6.82]	<0.0001
	30–39		1664	46	2.76% [2.02 – 3.69]	3.55% [2.70 – 4.57]	<0.0001
	40–49		2271	39	1.72% [1.22 – 2.35]	1.50% [1.04 – 2.09]
	50–59		2241	37	1.65% [1.16 – 2.28]	1.21% [0.79 – 1.75]
	≥60		1200	19	1.58% [0.95 – 2.47]	1.67% [1.02 – 2.57]
Province	Leinster		4955	136	2.74% [2.30 – 3.25]	2.95% [2.48 – 3.47]	<0.0001
	Munster		2257	37	1.64% [1.15 – 2.26]	1.86% [1.34 – 2.52]
	Ulster		648	9	1.39% [0.64 – 2.64]	1.39% [0.63 – 2.63]
	Connacht		649	5	0.77% [0.25 – 1.80]	1.23% [0.53 – 2.43]
Blood Grouping	ABO	A	2367	67	2.83% [2.19 – 3.58]
		B	964	17	1.76% [1.03 – 2.82]
		AB	203	6	2.96% [1.09 – 6.43]
		O	4975	97	1.95% [1.58 – 2.38]
	A antigen	+	2570	73	2.84% [2.22 – 3.57]		<0.0001
		−	5939	114	1.92% [1.58 – 2.31]
	RhD	+	6248	139	2.22% [1.87 – 2.63]
		−	2261	48	2.12% [1.57 – 2.82]

^⁎Adjusted to National demographic distributions recorded in the 2016 CENSUS www.CSO.ie.