TABLE 1.
Baseline Characteristics and Clinical Course of Infants Hospitalized Between March 15 and August 13, 2021, From 37 Sites in 26 States With Severe Compared With Nonsevere Acute COVID-19 and Initial Laboratory Values Within 48 Hours of Admission*
| All Infants (n=206) | Severe COVID-19 (n = 104) | Nonsevere COVID-19 (n = 102) | P | |
|---|---|---|---|---|
| Age (mo) | 1 (0–3) | 1 (1–4) | 1 (0–2) | 0.001 |
| 7–28 d of life | 58 (28.2%) | 20 (19.2%) | 38 (37.3%) | 0.008 |
| 1 to <3 mo | 89 (43.2%) | 45 (43.3%) | 44 (43.1%) | |
| 3 to <6 mo | 31 (15.0%) | 20 (19.2%) | 11 (10.8%) | |
| 6 to <12 mo | 28 (13.6%) | 19 (18.3%) | 9 (8.8%) | |
| Sex, race and ethnicity† | ||||
| Male sex | 112 (54.4%) | 58 (55.8%) | 54 (52.9%) | 0.78 |
| White, non-Hispanic | 36 (17.5%) | 22 (21.2%) | 14 (13.7%) | 0.20 |
| Black, non-Hispanic | 40 (19.4%) | 22 (21.2%) | 18 (17.6%) | |
| Hispanic or Latino | 91 (44.2%) | 46 (44.2%) | 45 (44.1%) | |
| Other, non-Hispanic | 15 (7.3%) | 4 (3.8%) | 11 (10.8%) | |
| Unknown | 24 (11.7%) | 10 (9.6%) | 14 (13.7%) | |
| At least one underlying condition‡ | 40 (19.4%) | 33 (31.7%) | 7 (6.9%) | <0.001 |
| Respiratory | 9 (4.4%) | 9 (8.7%) | 0 (0%) | 0.003 |
| Cardiovascular | 14 (6.8%) | 13 (12.5%) | 1 (1.0%) | 0.001 |
| Neurologic | 10 (4.9%) | 7 (6.7%) | 3 (2.9%) | 0.33 |
| Other underlying condition | 32 (15.5%) | 27 (26.0%) | 5 (4.9%) | <0.001 |
| Prematurity | ||||
| Premature | 25 (12.1%) | 16 (15.4%) | 9 (8.8%) | 0.20 |
| <28 weeks | 2/25 (8.0%) | 2/16 (12.5%) | 0/9 (0%) | 0.52 |
| 29–33 weeks | 2/25 (8.0%) | 2/16 (12.5%) | 0/9 (0%) | 0.52 |
| 34–36 weeks | 21/25 (84.0%) | 12/16 (75.0%) | 9/9 (100.0%) | 0.26 |
| Presentation conditions | ||||
| Duration of symptoms pre-hospitalization (d) | 1 (1–2.5) | 1 (1–3) | 1 (1–2) | 0.37 |
| Organ systems involved§ | 2 (1–2) | 2 (1–3) | 1 (0–1) | <0.001 |
| Signs and symptoms on presentation¶ | ||||
| Constitutional | 167 (81.1%) | 74 (71.2%) | 93 (91.2%) | <0.001 |
| Gastrointestinal | 101 (49.0%) | 48 (46.2%) | 53 (52.0%) | 0.49 |
| Mucocutaneous | 23 (11.2%) | 14 (13.5%) | 9 (8.8%) | 0.38 |
| Lower respiratory | 97 (47.1%) | 64 (61.5%) | 33 (32.4%) | <0.001 |
| Upper respiratory | 73 (35.4%) | 38 (36.5%) | 35 (34.3%) | 0.77 |
| Neurologic | 25 (12.1%) | 20 (19.2%) | 5 (4.9%) | 0.002 |
| Initial laboratory values | ||||
| Absolute lymphocyte count (103 cells/μL) | 3.68 (2.5–5.3) | 3.72 (1.89–5.25) | 3.64 (2.68–5.35) | 0.75 |
| Absolute neutrophil count (103 cells/μL) | 2.65 (1.48–4.0) | 3.17 (1.8–5.18) | 2.03 (1.35–3.09) | 0.002 |
| Neutrophil:lymphocyte ratio | 0.77 (0.40–1.19) | 0.91 (0.5–1.31) | 0.6 (0.33–1.06) | 0.007 |
| Platelet count (103 cells/μL) | 325 (250–397) | 355 (268–416) | 310 (242–362) | 0.054 |
| Hemoglobin (g/dL) | 11.7 (10.7–13.2) | 11.3 (10.5–12.6) | 12 (10.9–13.9) | 0.02 |
| ALT (U/L) | 29 (23–38) | 30.5 (23–50) | 27 (23.25–33) | 0.12 |
| CRP (mg/dL) | 0.5 (0.27–1.65) | 0.5 (0.33–2.0) | 0.5 (0.25–0.88) | 0.54 |
| Clinical course and outcomes | ||||
| ICU/HAU admission | 41 (19.9%) | 32 (30.8%) | 9 (8.8%) | <0.001 |
| Hospital length of stay (d) | 2 (1–2) | 2 (1–4) | 1 (1–2) | <0.001 |
| Any respiratory support | 40 (19.4%) | 40 (38.5%) | 0 (0%) | <0.001 |
| Mechanical ventilation | 10 (4.9%) | 10 (9.6%) | 0 (0%) | 0.002 |
| Vasopressor requirement | 5 (2.4%) | 5 (4.8%) | 0 (0%) | 0.06 |
| ECMO | 1 (0.5%) | 1 (1.0%) | 0 (0%) | 1.00 |
| Death | 1 (0.5%) | 1 (1.0%) | 0 (0%) | 1.00 |
Continuous variables are expressed as median and IQR, while discrete variables are expressed as counts and percentages.
*Severe acute COVID-19 was defined as severe complications involving 1 organ system or more and evidence of infection with severe acute respiratory syndrome coronavirus 2 based on having a positive RT-PCR test result as previously as defined by previously outlined criteria4 (Table, Supplemental Digital Content 4, http://links.lww.com/INF/E610; Fig. 1B).
†Race and ethnicity were recorded from hospital medical records as reported by the site clinicians who cared for the patients.
‡Underlying conditions excluded obesity. Other category includes oncologic, immunosuppressive, rheumatologic, autoimmune, hematologic, renal, urologic, gastrointestinal, hepatic, endocrine and metabolic conditions. Respiratory conditions include “asthma,” chronic restrictive lung disease, tracheomalacia/bronchomalacia, bronchopulmonary dysplasia, cystic fibrosis, obstructive sleep apnea, recurrent aspiration into lungs or pulmonary hypertension, as well as other underlying conditions judged by the study team to involve the respiratory system. Cardiovascular includes congenital heart disease (nonspecific), acquired heart disease (nonspecific), history of cardiac repair, as well as other underlying conditions judged by the study team to involve the cardiovascular system.
§Organ systems involved includes cardiovascular, respiratory, renal, neurologic, gastrointestinal, hematologic, mucocutaneous and musculoskeletal.
¶Presenting signs and symptoms were recorded from hospital medical records and included constitutional symptoms (fever, fatigue, muscle aches/joint pain), gastrointestinal symptoms (nausea/refusal to eat, vomiting, abdominal pain, diarrhea), upper respiratory (rhinorrhea, congestion, sore throat), lower respiratory (cough, shortness of breath, chest pain, wheezing, lower chest wall indrawing), mucocutaneous findings (rash, inflammation of the oral mucosa, conjunctivitis and extremity findings, including erythema or edema of the hands or feet, or periungual peeling), hematologic signs (abnormal cell counts or clotting function) and neurologic symptoms (headache, altered mental status/confusion).
ALT indicates alanine aminotransferase; CRP, C-reactive protein; ECMO, extracorporeal membrane oxygenation; HAU, high acuity unit; RT-PCR, reverse transcription–polymerase chain reaction.