TABLE 1. Characteristics of multisystem inflammatory syndrome in children case-patients and controls aged 12–18 years — 24 pediatric hospitals, 20 U.S. states,* July 1–December 9, 2021.
| Characteristic | No. (%) |
|||
|---|---|---|---|---|
| Total |
MIS-C case-patients |
Controls |
p-value† | |
| (N = 283) | (n = 102) | (n = 181) | ||
|
Median age, yrs (IQR)
|
14.5 (13.4–15.9) |
14.2 (13.0–15.9) |
14.7 (13.6–15.9) |
0.06 |
|
Age group, yrs
| ||||
| 12–15 |
221 (78.1) |
81 (79.4) |
140 (77.3) |
0.77 |
| 16–18 |
62 (21.9) |
21 (20.6) |
41 (22.7) |
|
|
Sex
| ||||
| Female |
132 (46.6) |
30 (29.4) |
102 (56.4) |
<0.01 |
|
Race/Ethnicity
| ||||
| White, non-Hispanic |
105 (37.1) |
32 (31.4) |
73 (40.3) |
0.39 |
| Black, non-Hispanic |
99 (35.0) |
42 (41.2) |
57 (31.5) |
|
| Asian, non-Hispanic |
8 (2.8) |
1 (1.0) |
7 (3.9) |
|
| Hispanic, any race |
51 (18.0) |
19 (18.6) |
32 (17.7) |
|
| Multiple/Other, non-Hispanic |
10 (3.5) |
4 (3.9) |
6 (3.3) |
|
| Unknown |
10 (3.5) |
4 (3.9) |
6 (3.3) |
|
|
SVI,§ median (IQR)
|
0.60 (0.30–0.80) |
0.64 (0.43–0.78) |
0.56 (0.27–0.81) |
0.09 |
|
U.S. Census region*
| ||||
| Northeast |
8 (2.8) |
3 (2.9) |
5 (2.8) |
0.98 |
| Midwest |
75 (26.5) |
28 (27.5) |
47 (26.0) |
|
| South |
159 (56.2) |
56 (54.9) |
103 (56.9) |
|
| West |
41 (14.5) |
15 (14.7) |
26 (14.4) |
|
|
Month of admission
| ||||
| June |
1 (0.4) |
0 (—) |
1 (0.6) |
0.35 |
| July |
9 (3.2) |
5 (4.9) |
4 (2.2) |
|
| August |
49 (17.3) |
16 (15.7) |
33 (18.2) |
|
| September |
82 (29.0) |
35 (34.3) |
47 (26.0) |
|
| October |
85 (30.0) |
30 (29.4) |
55 (30.4) |
|
| November |
48 (17.0) |
15 (14.7) |
33 (18.2) |
|
| December |
9 (3.2) |
1 (1.0) |
8 (4.4) |
|
|
Underlying health condition¶
| ||||
| At least one underlying condition (including obesity) |
164 (58.0) |
40 (39.2) |
124 (68.5) |
<0.01 |
| Asthma |
49 (17.3) |
15 (14.7) |
34 (18.8) |
0.42 |
| Cardiovascular system disorder |
23 (8.1) |
3 (2.9) |
20 (11.0) |
0.02 |
| Neurologic/Neuromuscular disorder |
45 (15.9) |
7 (6.9) |
38 (21.0) |
<0.01 |
| Active or previous oncologic disorder |
9 (3.2) |
1 (1.0) |
8 (4.4) |
0.16 |
| Nononcologic immunosuppressive disorder |
13 (4.6) |
2 (2.0) |
11 (6.1) |
0.14 |
| Endocrine disorder |
16 (5.7) |
4 (3.9) |
12 (6.6) |
0.43 |
| Diabetes |
9 (3.2) |
2 (2.0) |
7 (3.9) |
0.50 |
| Other chronic conditions** |
97 (34.3) |
21 (20.6) |
76 (42.0) |
<0.01 |
|
Laboratory test results††
| ||||
| RT-PCR or antigen-positive, antibody not performed |
11 (3.9) |
11 (10.8) |
0 (—) |
<0.01 |
| RT-PCR or antigen-positive, antibody-positive |
12 (4.2) |
12 (11.8) |
0 (—) |
|
| Antibody positive only |
76 (26.9) |
76 (74.5) |
0 (—) |
|
| Pre-admission results available only |
3 (1.1) |
3 (2.9) |
0 (—) |
|
|
Fully vaccinated§§
|
70 (24.7) |
5 (4.9) |
65 (35.9) |
<0.01 |
| Median interval from receipt of second vaccine dose to reference hospitalization date, days (IQR)¶¶ | 84 (51–122) | 63 (48–89) | 88 (52–122) | 0.37 |
Abbreviations: MIS-C = multisystem inflammatory syndrome in children; RT-PCR = reverse transcription-polymerase chain reaction; SVI = social vulnerability index.
* Patients included vaccinated and unvaccinated persons aged 12–18 years enrolled from 24 pediatric hospitals in 20 states. Northeast: Boston Children’s Hospital (Massachusetts), Children's Hospital of Philadelphia (Pennsylvania), and Saint Barnabas Medical Center (New Jersey); Midwest: Akron Children’s Hospital (Ohio), Children’s Hospital and Medical Center: Nebraska (Nebraska), Children's Hospital of Michigan (Michigan), Children’s Mercy Kansas City (Missouri), Cincinnati Children’s Hospital Medical Center (Ohio), Lurie Children's Hospital of Chicago (Illinois), Mayo Clinic (Minnesota), Nationwide Children's Hospital (Ohio), and Riley Children's Hospital (Indiana); South: Arkansas Children’s Hospital (Arkansas), Children’s of Alabama (Alabama), Children's Healthcare of Atlanta (Georgia), Children’s Hospital of New Orleans (Louisiana), Medical University of South Carolina Children’s Health (South Carolina), Monroe Carell Jr. Children’s Hospital at Vanderbilt (Tennessee), Texas Children’s Hospital (Texas), University of Mississippi Medical Center (Mississippi), University of North Carolina at Chapel Hill Children’s Hospital (North Carolina), and University of Texas Southwestern Medical Center (Texas); West: Children’s Hospital Colorado (Colorado), Children’s Hospital Los Angeles (California), University of California San Diego-Rady Children’s Hospital (California), and University of California San Francisco Benioff Children’s Hospital Oakland (California).
† Testing for statistical significance was conducted using Fisher's exact test to compare categorical variables or Wilcoxon rank-sum test for medians to compare continuous data. Statistical significance was defined as p<0.05.
§ CDC/ATSDR SVI documentation is available at https://www.atsdr.cdc.gov/placeandhealth/svi/index.html. Median SVI for case-patients and controls are based on U.S. 2018 SVI data.
¶ Underlying conditions with a missing response (yes/no) were assumed not to be present.
** Other chronic conditions included rheumatologic/autoimmune disorder, hematologic disorder, renal or urologic dysfunction, gastrointestinal/hepatic disorder, metabolic or confirmed or suspected genetic disorder (including obesity), or atopic or allergic condition.
†† With the exception of the “pre-admission results available only” category, all other test results were obtained after hospital admission.
§§ COVID-19 vaccination status included the following two categories: 1) unvaccinated, defined as no receipt of any SARS-CoV-2 vaccine before hospitalization for current illness and 2) fully vaccinated, defined as receipt of both doses of a 2-dose Pfizer-BioNTech vaccination ≥28 days before illness onset.
¶¶ Dates are based on those with documented vaccination, not plausible self-report. For controls without COVID-19–like illness, a reference date was set to the admission date of their matched case-patient to account for residual confounding by hospital admission date relative to expanding vaccination coverage.