Table 4.

Prevalence of SARS-CoV-2 antibodies by COVID-19-related characteristics, both hospitals

Participant characteristics	Total	SARS-CoV-2 IgG detected		P valuea
	N	n	% (95% CI)
Contact of a COVID-19 case
Yes	1704	325	19 (17–21)	<0.001
No	249	249	6.1 (5.4–6.9)
Missing	10	2	167 (2.1–48)
Setting of close contact
Contact at work	1495	269	18 (16–20)	0.002
Contact outside of work	209	56	27 (21–33)
Workplace exposure
Daily contact with COVID-19 patients	902	136	15 (13–18)	<0.001
Daily contact with patients without COVID	3245	344	11 (9.6–12)
No patients contact	1635	96	5.9 (4.9–7.1)
Previous COVID-19-like symptoms
No symptoms	2876	92	3.2 (2.6–3.9)	<0.001
Had symptoms	2911	484	17 (15–18)
Previous COVID-19 PCR test
Yes	2778	474	17 (16–19)	<0.001
No	3003	102	3.4 (2.8–4.1)
Previous positive COVID-19 PCR test
Yes	367	350	95.4 (92.7–97.3)	<0.001
No	5414	226	4.2 (3.7–4.7)

^aCalculated using the χ² test.