Low Seroprevalence of SARS-CoV-2 in Rhode Island blood donors during may 2020 as determined using multiple serological assay formats

Table 2 Antibody test results and seroprevalence estimates overall and by sex, age and race/ethnicity. Seroprevalence estimates reported in terms of posterior mode and 95% credible interval, calculated using Bayesian method that adjusts for test sensitivity and specificity. Estimates not reported for categories with 25 test results or fewer. Excludes 11 positive CP/WB Donors and 2 CP/WB donors that tested negative for all three tests. *Posterior mode calculated using a prior distribution having mode equal to the overall seroprevalence for IgM

		Number Positive			Seroprevalence Estimates (95% CI)
	N	IgG	IgM	Ortho	IgG	IgM	Ortho
Overall	1996	13	68	14	0.6 (0.3 to 1.1)	2.7 (1.7 to 3.8)	0.6 (0.2 to 1.1)
Sex
Men	1057	9	32	11	0.8 (0.4 to 1.6)	2.2 (1.1 to 3.8)	0.9 (0.3 to 1.8)
Women	939	4	36	3	0.3 (0.1 to 1.1)	3.1 (1.8 to 5.0)	0.1 (0 to 0.9)
Age
15–34	348	2	4	5	0.6 (0.1 to 2.1)	0.2 (0 to 2.4)	1.3 (0.4 to 3.4)
35–64	1181	5	45	6	0.4 (0.1 to 1.0)	3.3 (1.9 to 4.8)	0.4 (0 to 1.0)
65+	467	6	19	3	1.2 (0.5 to 2.8)	3.4 (1.6 to 6.1)	0.5 (0.1 to 1.8)
Race/Ethnicity
Asian	5	0	0	0
Black/African American	11	0	0	0
Hispanic/Latino	54	1	0	1	1.9 (0.4 to 10.2)	0.5 (0 to 7.7) *	1.8 (0.3 to 10.3)
Native American	5	0	0	0
White	1688	10	57	11	0.5 (0.2 to 1.1)	2.7 (1.6 to 3.9)	0.5 (0.1 to 1.1)
Other / Multiple	24	0	2	0
Unknown / Declined	209	2	8	2	0.9 (0.2 to 3.5)	3.0 (0.9 to 7.5)	0.8 (0.1 to 3.5)

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