Table 1.

Baseline characteristics of propensity score-matched veterans infected during Omicron and Delta predominant periods.

Characteristic	Omicron predominant infection period N = 22,841	Delta predominant infection period N = 22,841
Age
Median (IQR)	62.0 (49.0, 72.0)	62.0 (49.0, 72.0)
18–39 years	3370 (14.8)	3370 (14.8)
40–49 years	2595 (11.4)	2595 (11.4)
50–59 years	4161 (18.2)	4161 (18.2)
60–69 years	4,904 (21.5)	4904 (21.5)
70–79 years	6453 (28.3)	6453 (28.3)
80–89 years	1176 (5.1)	1176 (5.1)
≥ 90 years	182 (0.8)	182 (0.8)
Sex
Male	21,000 (91.9)	21,000 (91.9)
Female	1841 (8.1)	1841 (8.1)
aRace
White	18,811 (82.4)	18,811 (82.4)
Black	2638 (11.5)	2638 (11.5)
Other or missing	1392 (6.1)	1392 (6.1)
Body Mass Index (median, IQR)	30.0 (26.5, 34.1)	30.2 (26.6, 34.4)
Charlson Comorbidity Index (median, IQR)	3 (2, 4)	3 (2, 4)
Comorbidities
Hypertension	13,369 (58.5)	13,538 (59.3)
Diabetes	6447 (28.2)	6863 (30.0)
Chronic obstructive pulmonary disease	5002 (21.9)	5033 (22.0)
Chronic kidney disease	2449 (10.7)	2575 (11.3)
Congestive heart failure	1998 (8.7)	2094 (9.2)
Malignancy	2062 (9.0)	1974 (8.6)
Vaccination status at the time of infection
Not vaccinated at time of infection	12,977 (56.8)	12,977 (56.8))
Received at least one vaccine dose at the time of infection	9864 (43.2)	9864 (43.2)
Vaccinated with only 1 dose at time of infection	1481 (6.5))	1481 (6.5)
Vaccinated with 2nd dose < 3 months prior to infection	44 (0.2)	85 (0.4)
Vaccinated with 2nd dose ≥ 3 months prior to infection	7349 (32.2)	7308 (32.0)
Vaccinated with 3rd dose prior to infection	990 (4.3)	990 (4.3)
Infection status in relation to vaccination
Infection before or up to 14 days of 2nd dose	1488 (6.5)	1509 (6.6)
Infection post 14 days of 2nd dose up to 14 days post 3rd dose	7466 (32.7)	7952 (34.8)
Infection ≥ 14 days after 3rd dose	910 (4.0%)	403 (1.8%)

^aDetailed racial categories for both groups are provided in Supplementary Table 6.