Table 1.

Demographic characteristics and antibody levels in the study subjects

	African-American		Caucasian-American		Hispanic-American
	N	%	N	%	N	%
Gender
Male	174	80.2	422	72.8	150	69.1
Female	43	19.8	158	27.2	67	30.9
Self-Declared Race
African American	184	84.8	0	0.0	0	0.0
Caucasian	0	0.0	531	91.6	39	18.0
More than one race	19	8.8	34	5.9	32	14.7
Other or do not know	14	6.5	15	2.6	146	67.3
Self-Declared Ethnicity
Not Hispanic	179	82.5	544	93.8	25	11.5
Hispanic	14	6.5	24	4.1	188	86.6
Do not know	24	11.1	12	2.1	4	1.8
Age Category
19-21	49	22.6	133	22.9	48	22.1
22-23	39	18.0	156	26.9	54	24.9
24-27	54	24.9	167	28.8	64	29.5
28-40	75	34.6	124	21.4	51	23.5
Time from Immunization to Blood Draw
1-8 months	53	24.4	149	25.6	49	22.6
9-14 months	46	21.2	147	25.3	58	26.7
15-33 months	44	20.3	161	27.8	60	27.6
34-48 months	74	34.1	123	21.2	50	23.0
	Mean	St. Dev.	Mean	St. Dev.	Mean	St. Dev.
Antibody Level (ID₅₀) ^a	168.6	118.7	162.5	128.8	153.5	100.5
	Median	IQR	Median	IQR	Median	IQR
	132.5	80.1-226.6	131.2	76.9-202.2	135.5	80.0-190.9

St. Dev, standard deviation; IQR, interquartile range.

Values are in ID₅₀ values as measured by the β-galactosidase based vaccinia-specific neutralization assay.