. 2021 Nov 2;4(11):e2132540. doi: 10.1001/jamanetworkopen.2021.32540

Table 1. Clinical Characteristics of Vaccinated and 1:10 Propensity-Matched Unvaccinated Cohorts.

Clinical covariate	Individuals, No. (%)		Standardized mean difference
Clinical covariate	Vaccinated cohort (n = 8889)	1:10 Propensity-matched unvaccinated cohort (n = 88 898)	Standardized mean difference
Age (overall), y	52.4 (16.9)	51.7 (16.7)	0.04^a
18-24	697 (7.8)	7286 (8.2)	0.01^a
25-34	932 (10.5)	9752 (11.0)	0.02^a
35-44	1360 (15.3)	13 978 (15.7)	0.01^a
45-54	1556 (17.5)	15 547 (17.5)	0.00^a
55-64	2019 (22.7)	20 980 (23.6)	0.02^a
65-74	1647 (18.5)	16 424 (18.5)	0.00^a
≥75	678 (7.6)	4931 (5.5)	0.09^a
Ethnicity
Hispanic or Latino	312 (3.5)	3060 (3.4)	0.00^a
Not Hispanic or Latino	8202 (92.3)	81 458 (91.6)	0.02^a
Unknown	375 (4.2)	4380 (4.9)	0.03^a
Sex
Female	4397 (49.5)	44 140 (49.7)	0.00^a
Male	4491 (50.5)	44 748 (50.3)	0.00^a
Unknown	1 (0.01)	10 (0.01)	0.00^a
Patients in long-term care	22 (0.2)	319 (0.4)	0.02^a
Race
Asian	191 (2.1)	1605 (1.8)	0.03^a
Black or African American	274 (3.1)	2281 (2.6)	0.03^a
Native American	31 (0.3)	267 (0.3)	0.01^a
Native Hawaiian or Pacific Islander	12 (0.1)	100 (0.1)	0.01^a
White	7945 (89.4)	79 692 (89.6)	0.01^a
Other	222 (2.5)	2413 (2.7)	0.01^a
Unknown	214 (2.4)	2540 (2.9)	0.03^a
State of residence
Minnesota	5503 (61.9)	55 213 (62.1)	0.00^a
Wisconsin	2192 (24.7)	21 817 (24.5)	0.00^a
Arizona	541 (6.1)	5410 (6.1)	0.00^a
Florida	514 (5.8)	5140 (5.8)	0.00^a
Iowa	78 (0.9)	767 (0.9)	0.00^a
Nevada	9 (0.1)	90 (0.1)	0.00^a
North Dakota	27 (0.3)	258 (0.3)	0.00^a
Arkansas	2 (0.02)	8 (0.01)	0.01^a
Nebraska	2 (0.02)	20 (0.02)	0.00^a
Illinois	9 (0.10)	85 (0.10)	0.00^a
Georgia	1 (0.01)	10 (0.01)	0.00^a
South Dakota	8 (0.09)	59 (0.07)	0.01^a
Washington	1 (0.01)	8 (0.01)	0.00^a
Michigan	1 (0.01)	6 (0.01)	0.01^a
Oregon	1 (0.01)	7 (0.01)	0.00^a
Previous PCR tests (overall)	1.098 (1.327)	1.136 (0.963)	0.04^a
0	3734 (42.0)	19 331 (21.8)	0.48
1	2789 (31.4)	49 252 (55.4)	0.49
2	1183 (13.3)	13 455 (15.1)	0.05^a
3	521 (5.9)	4020 (4.5)	0.06^a
4	265 (3.0)	1462 (1.6)	0.1^a
≥5	397 (4.5)	1378 (1.6)	0.22^a
Follow-up period, d
Mean (SD)	103 (246)	103 (246)
Median (IQR)	111 (102-131)	111 (102-131)

Abbreviation: PCR, polymerase chain reaction.

^{^a}

Highly balanced covariates with a standardized mean difference of less than 0.1. Covariates for balancing include (1) demographic characteristics (age, sex, race, and ethnicity), (2) number of prior PCR tests (number of PCR tests that the individual received before February 27, 2021), and (3) location (zip code). The zip code is matched exactly between the 2 cohorts, so the proportion of individuals in each state is identical.