TABLE 1. Characteristics of hospitalizations among immunocompetent adults aged ≥18 years with COVID-19–like illness,* by COVID-19 vaccination status and SARS-CoV-2 test result — seven states,† September 2022–April 2023.
| Characteristic | Overall, no. (column %) | SARS-CoV-2 test result status, no. (row %) |
SMD§ | Vaccination status,¶ no. (row %) |
SMD§ | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| Case-patients (positive) | Control patients (negative) | Unvaccinated | Primary series with or without MV booster, ≥7 days earlier** | BV mRNA dose, 7–59 days earlier | BV mRNA dose, 60–119 days earlier | BV mRNA dose, 120–179 days earlier | ||||
|
All hospitalizations (row %)
|
66,141
(100.0)
|
6,907
(10.4)
|
59,234
(89.6)
|
NA
|
15,514
(23.5)
|
37,269
(56.3)
|
4,857
(7.3)
|
5,191
(7.8)
|
3,310
(5.0)
|
NA
|
|
Variant-predominant period††
| ||||||||||
| BA.4/BA.5–related |
47,065
(71.2)
|
5,219
(11.1) |
41,846
(88.9) |
0.11 |
11,240
(23.9) |
27,594
(58.6) |
4,439
(9.4) |
3,525
(7.5) |
267
(0.6) |
1.09 |
| XBB-related |
19,076
(28.8)
|
1,688
(8.8) |
17,388
(91.2) |
4,274
(22.4) |
9,675
(50.7) |
418
(2.2) |
1,666
(8.7) |
3,043
(16.0) |
||
|
Site
| ||||||||||
| HealthPartners |
5,354
(8.1)
|
646
(12.1) |
4,708
(87.9) |
0.11 |
969
(18.1) |
2,716
(50.7) |
678
(12.7) |
643
(12.0) |
348
(6.5) |
2.72 |
| Intermountain Healthcare |
7,572
(11.4)
|
933
(12.3) |
6,639
(87.7) |
2,041
(27.0) |
3,994
(52.7) |
538
(7.1) |
595
(7.9) |
404
(5.3) |
||
| KPCHR |
4,974
(7.5)
|
414
(8.3) |
4,560
(91.7) |
1,232
(24.8) |
2,565
(51.6) |
458
(9.2) |
465
(9.3) |
254
(5.1) |
||
| KPNC |
23,294
(35.2)
|
2,271
(9.7) |
21,023
(90.3) |
2,147
(9.2) |
15,152
(65.0) |
2,017
(8.7) |
2,338
(10.0) |
1,640
(7.0) |
||
| Regenstrief Institute |
24,947
(37.7)
|
2,643
(10.6) |
22,304
(89.4) |
9,125
(36.6) |
12,842
(51.5) |
1,166
(4.7) |
1,150
(4.6) |
664
(2.7) |
||
|
Age group, yrs
| ||||||||||
| 18–49 |
9,656
(14.6)
|
552
(5.7) |
9,104
(94.3) |
0.35 |
4,047
(41.9) |
4,880
(50.5) |
288
(3.0) |
283
(2.9) |
158
(1.6) |
2.25 |
| 50–64 |
13,200
(20.0)
|
995
(7.5) |
12,205
(92.5) |
3,986
(30.2) |
7,488
(56.7) |
671
(5.1) |
652
(4.9) |
403
(3.1) |
||
| 65–74 |
15,002
(22.7)
|
1,496
(10.0) |
13,506
(90.0) |
3,206
(21.4) |
8,531
(56.9) |
1,240
(8.3) |
1,242
(8.3) |
783
(5.2) |
||
| 75–84 |
16,791
(25.4)
|
2,155
(12.8) |
14,636
(87.2) |
2,702
(16.1) |
9,671
(57.6) |
1,582
(9.4) |
1,726
(10.3) |
1,110
(6.6) |
||
| ≥85 |
11,492
(17.4)
|
1,709
(14.9) |
9,783
(85.1) |
1,573
(13.7) |
6,699
(58.3) |
1,076
(9.4) |
1,288
(11.2) |
856
(7.4) |
||
|
Sex
| ||||||||||
| Men |
30,327
(45.9)
|
3,412
(11.3) |
26,915
(88.7) |
0.08 |
7,503
(24.7) |
16,802
(55.4) |
2,163
(7.1) |
2,333
(7.7) |
1,526
(5.0) |
0.23 |
| Women |
35,814
(54.1)
|
3,495
(9.8) |
32,319
(90.2) |
8,011
(22.4) |
20,467
(57.1) |
2,694
(7.5) |
2,858
(8.0) |
1,784
(5.0) |
||
|
Race and ethnicity
| ||||||||||
| Black or African American, non-Hispanic |
5,953
(9.0)
|
481
(8.1) |
5,473
(91.9) |
0.11 |
1,923
(32.3) |
3,317
(55.7) |
263
(4.4) |
275
(4.6) |
175
(2.9) |
1.17 |
| White, non-Hispanic |
45,101
(68.2)
|
4,976
(11.0) |
40,125
(89.0) |
10,399
(23.1) |
24,751
(54.9) |
3,593
(8.0) |
3,892
(8.6) |
2,466
(5.5) |
||
| Hispanic or Latino |
5,622
(8.5)
|
517
(9.2) |
5,105
(90.8) |
944
(16.8) |
3,736
(66.5) |
364
(6.5) |
350
(6.2) |
228
(4.1) |
||
| Other,§§ non-Hispanic |
6,054
(9.2)
|
566
(9.3) |
5,488
(90.7) |
926
(15.3) |
3,716
(61.4) |
496
(8.2) |
553
(9.1) |
363
(6.0) |
||
| Unknown |
3,411
(5.2)
|
367
(10.8) |
3,044
(89.2) |
1,322
(38.8) |
1,749
(51.3) |
141
(4.1) |
121
(3.5) |
78
(2.3) |
||
|
SARS-CoV-2 test result status
| ||||||||||
| Case-patients (positive) |
6,907
(10.4)
|
6,907
(100.0) |
0
(—) |
NA |
1,791
(25.9) |
3,988
(57.7) |
327
(4.7) |
486
(7.0) |
315
(4.6) |
NA |
| Control patients (negative) |
59,234
(89.6)
|
0
(—) |
59,234
(100.0) |
13,723
(23.2) |
33,281
(56.2) |
4,530
(7.6) |
4,705
(7.9) |
2,995
(5.1) |
||
|
No. of MV doses received
| ||||||||||
| 0 |
15,599
(23.6)
|
1,798
(11.5) |
13,801
(88.5) |
NA |
15,514
(99.5) |
0
(—) |
36
(0.2) |
30
(0.2) |
19
(0.1) |
NA |
| 1 |
1,402
(2.1)
|
116
(8.3) |
1,286
(91.7) |
0
(—) |
1,259
(89.8) |
53
(3.8) |
54
(3.9) |
36
(2.6) |
||
| 2 |
12,948
(19.6)
|
1,340
(10.3) |
11,608
(89.7) |
0
(—) |
11,936
(92.2) |
404
(3.1) |
407
(3.1) |
201
(1.6) |
||
| 3 |
21,860
(33.1)
|
2,199
(10.1) |
19,661
(89.9) |
0
(—) |
16,684
(76.3) |
1,959
(9.0) |
1,972
(9.0) |
1,245
(5.7) |
||
| 4 |
14,332
(21.7)
|
1,454
(10.1) |
12,878
(89.9) |
0
(—) |
7,390
(51.6) |
2,405
(16.8) |
2,728
(19.0) |
1,809
(12.6) |
||
|
MV product received, by manufacturer¶¶
| ||||||||||
| Pfizer-BioNTech |
29,721
(58.7)
|
2,950
(9.9) |
26,771
(90.1) |
NA |
NA |
21,435
(72.1) |
3,018
(10.1) |
3,203
(10.8) |
2,065
(6.9) |
NA |
| Moderna |
23,048
(45.5)
|
2,384
(10.3) |
20,664
(89.7) |
NA |
16,887
(73.3) |
2,242
(9.7) |
2,409
(10.4) |
1,510
(6.6) |
||
| Janssen (Johnson & Johnson) |
3,230
(6.4)
|
286
(8.9) |
2,944
(91.1) |
NA |
2,770
(85.8) |
176
(5.4) |
177
(5.5) |
107
(3.3) |
||
| Novavax |
1 (0)
|
0 (—) |
1 (100.0) |
NA |
1 (100.0) |
0 (—) |
0 (—) |
0 (—) |
||
|
COVID-19 vaccination status
| ||||||||||
| Unvaccinated |
15,514
(23.5)
|
1,791
(11.5) |
13,723
(88.5) |
0.14 |
15,514
(100.0) |
0 (—) |
0 (—) |
0 (—) |
0 (—) |
NA |
| Primary series with or without MV booster |
37,269
(56.3)
|
3,988
(10.7) |
33,281
(89.3) |
0 (—) |
37,269
(100.0) |
0 (—) |
0 (—) |
0 (—) |
||
| mRNA BV dose, 7–59 days earlier |
4,857
(7.3)
|
327
(6.7) |
4,530
(93.3) |
0 (—) |
0 (—) |
4,857
(100.0) |
0 (—) |
0 (—) |
||
| mRNA BV dose, 60–119 days earlier |
5,191
(7.8)
|
486
(9.4) |
4,705
(90.6) |
0 (—) |
0 (—) |
0 (—) |
5,191
(100.0) |
0 (—) |
||
| mRNA BV dose, 120–179 days earlier |
3,310
(5.0)
|
315
(9.5) |
2,995
(90.5) |
0 (—) |
0 (—) |
0 (—) |
0 (—) |
3,310
(100.0) |
||
|
Most recent dose product manufacturer
| ||||||||||
| Pfizer-BioNTech |
29,892
(59.0)
|
2,968
(9.9) |
26,924
(90.1) |
0.04 |
0 (—) |
20,271
(67.8) |
3,441
(11.5) |
3,732
(12.5) |
2,448
(8.2) |
NA |
| Moderna |
19,084
(37.7)
|
2,004
(10.5) |
17,080
(89.5) |
0 (—) |
15,347
(80.4) |
1,416
(7.4) |
1,459
(7.6) |
862
(4.5) |
||
| Janssen (Johnson & Johnson) |
1,650
(3.3)
|
144
(8.7) |
1,506
(91.3) |
0 (—) |
1,650
(100.0) |
0 (—) |
0 (—) |
0 (—) |
||
| Novavax |
1 (0)
|
0 (—) |
1 (100.0) |
0 (—) |
1 (100.0) |
0 (—) |
0 (—) |
0 (—) |
||
|
One or more chronic respiratory condition
| ||||||||||
| Yes |
39,469
(59.7)
|
4,286
(10.9) |
35,183
(89.1) |
0.05 |
8,602
(21.8) |
22,383
(56.7) |
3,067
(7.8) |
3,314
(8.4) |
2,103
(5.3) |
0.46 |
| No |
26,672
(40.3)
|
2,621
(9.8) |
24,051
(90.2) |
6,912
(25.9) |
14,886
(55.8) |
1,790
(6.7) |
1,877
(7.0) |
1,207
(4.5) |
||
|
One or more chronic nonrespiratory condition
| ||||||||||
| Yes |
54,754
(82.8)
|
5,843
(10.7) |
48,911
(89.3) |
0.05 |
11,322
(20.7) |
31,413
(57.4) |
4,344
(7.9) |
4,679
(8.5) |
2,996
(5.5) |
1.28 |
| No |
11,387
(17.2)
|
1,064
(9.3) |
10,323
(90.7) |
4,192
(36.8) |
5,856
(51.4) |
513
(4.5) |
512
(4.5) |
314
(2.7) |
||
|
ICU admission
| ||||||||||
| Yes |
12,197
(18.4)
|
1,023
(8.4) |
11,174
(91.6) |
0.11 |
3,146
(25.8) |
6,763
(55.4) |
848
(7.0) |
886
(7.3) |
554
(4.5) |
0.22 |
| No |
53,944
(81.6)
|
5,884
(10.9) |
48,060
(89.1) |
12,368
(22.9) |
30,506
(56.6) |
4,009
(7.4) |
4,305
(8.0) |
2,756
(5.1) |
|
|
|
Receipt of invasive mechanical ventilation
| ||||||||||
| Yes |
3,293
(5.0)
|
250
(7.6) |
3,043
(92.4) |
0.08 |
804
(24.4) |
1,857
(56.4) |
229
(7.0) |
254
(7.7) |
149
(4.5) |
1.89 |
| No |
44,995
(68.0)
|
4,814
(10.7) |
40,181
(89.3) |
7,984
(17.7) |
26,340
(58.5) |
3,850
(8.6) |
4,151
(9.2) |
2,670
(5.9) |
||
| Unknown |
17,853
(27.0)
|
1,843
(10.3) |
16,010
(89.7) |
6,726
(37.7) |
9,072
(50.8) |
778
(4.4) |
786
(4.4) |
491
(2.8) |
||
|
In-hospital death***
| ||||||||||
| Yes |
2,735
(4.1)
|
331
(12.1) |
2,404
(87.9) |
0.04 | 727
(26.6) |
1,433
(52.4) |
183
(6.7) |
246
(9.0) |
146
(5.3) |
0.09 |
| No | 63,406 (95.9) | 6,576 (10.4) | 56,830 (89.6) | 14,787 (23.3) | 35,836 (56.5) | 4,674 (7.4) | 4,945 (7.8) | 3,164 (5.0) | ||
Abbreviations: BV = bivalent; ICU = intensive care unit; KPCHR = Kaiser Permanente Center for Health Research; KPNC = Kaiser Permanente Northern California; MV = monovalent; NA = not applicable; SMD = standardized mean or proportion difference.
* Hospitalizations with a discharge code consistent with COVID-19–like illness were included. COVID-19–like illness diagnoses included acute respiratory illness, respiratory signs or symptoms or febrile signs or symptoms using diagnosis codes from the International Classification of Diseases, Tenth Revision. Clinician-ordered molecular assays (e.g., real-time reverse transcription–polymerase chain reaction) for SARS-CoV-2 occurring ≤14 days before to <72 hours after the date of admission were included.
† California (September 13, 2022–April 21, 2023), Indiana (September 13, 2022–April 12, 2023), Minnesota and Wisconsin (September 13, 2022–April 21, 2023), Oregon and Washington (September 13, 2022–April 14, 2023), and Utah (September 13, 2022–April 21, 2023).
§ An absolute SMD >0.20 indicates a nonnegligible difference in variable distributions between hospitalizations for vaccinated versus unvaccinated patients, or for patients with a positive SARS-CoV-2 test result versus patients with a negative SARS-CoV-2 test result. For mRNA COVID-19 vaccination status, a single SMD was calculated by averaging the absolute SMDs obtained from pairwise comparisons of each vaccinated category versus unvaccinated. Specifically, it was calculated as the average of the absolute value of the SMDs for 1) vaccinated with only MV doses, ≥7 days earlier versus unvaccinated, 2) vaccinated with an mRNA BV dose, 7–59 days earlier versus unvaccinated, 3) vaccinated with an mRNA BV dose, 60–119 days earlier versus unvaccinated, and 4) vaccinated with an mRNA BV dose, 120–179 days earlier versus unvaccinated.
¶ Vaccination was defined as having received the last MV or BV dose within the specified range of days before the index date, which was the date of respiratory specimen collection associated with the most recent positive or negative SARS-CoV-2 test result before the admission date, or the admission date if testing only occurred after the admission.
** Includes persons who received a single dose of Janssen (Johnson & Johnson) vaccine. Persons who received a single dose of Pfizer-BioNTech, Moderna, or Novavax vaccine were excluded from the analysis.
†† Variant predominance was defined as the period when a variant accounted for ≥50% of all sequenced specimens in the U.S. Department of Health and Human Services region where the site is located. XBB-related sublineages predominated at Intermountain Healthcare beginning January 28, 2023; at HealthPartners, KPNC, and Regenstrief Institute beginning February 4, 2023; and at KPCHR beginning February 11, 2023.
§§ Other race includes American Indian or Alaska Native, Asian, Native Hawaiian or other Pacific Islander, other races not listed, and multiple races. Because of small numbers, these categories were combined.
¶¶ Because persons might have received vaccine from more than one manufacturer, columns might sum to >100%.
*** In-hospital death was identified at each individual site and was defined as a death while hospitalized or ≤28 days after admission.