Table 2.
Clinical characteristics on admission in the Delta and Omicron variant predominant periods by age group.
| Patient characteristics | Total | <3 months | 3 to <24 months | 2 to <6 years | 6 to <13 years | ≥13 years |
|---|---|---|---|---|---|---|
| Number of cases | ||||||
| Delta predominant period | 458 | 20 | 74 | 88 | 142 | 134 |
| Omicron predominant period | 389 | 27 | 86 | 67 | 116 | 93 |
| Asymptomatic cases | ||||||
| Delta predominant period | 61 (13.3) | 3 (15.0) | 14 (18.9) | 17 (19.3) | 23 (16.2) | 4 (3.0) |
| Omicron predominant period | 18 (4.6) | 1 (3.7) | 5 (5.8) | 9 (13.4) | 1 (0.9) | 2 (2.2) |
| Body temperature (°C) | ||||||
| Delta predominant period | 37.2 (36.7–37.9) | 37.5 (37.1–38.0) | 37.2 (36.7–37.7) | 37.1 (36.7–37.7) | 37.0 (36.7–37.6) | 37.2 (36.8–38.0) |
| Omicron predominant period | 37.5 (36.9–38.5) | 37.6 (37.2–38.3) | 37.6 (37.0–38.9) | 37.8 (37.0–38.5) | 37.7 (36.9–38.5) | 37.2 (36.8–38.1) |
| Fever ≥ 38.0°C | ||||||
| Delta predominant period | 109 (23.8) | 7 (35.0) | 22 (29.7) | 18 (20.5) | 27 (19.0) | 35 (26.1) |
| Omicron predominant period | 145 (37.3) | 9 (33.3) | 38 (44.2) | 29 (43.3) | 43 (37.1) | 26 (28.0) |
| SpO2 < 96% under room air | ||||||
| Delta predominant period | 18 (4.1) | 1 (5.6) | 4 (5.6) | 4 (4.8) | 3 (2.1) | 6 (4.7) |
| Omicron predominant period | 16 (4.3) | 1 (3.7) | 4 (4.9) | 2 (3.2) | 5 (4.5) | 4 (4.5) |
| Runny nose | ||||||
| Delta predominant period | 108 (23.6) | 8 (40.0) | 29 (39.2) | 17 (19.3) | 26 (18.3) | 28 (20.9) |
| Omicron predominant period | 91 (23.4) | 10 (37.0) | 33 (38.4) | 17 (25.4) | 14 (12.1) | 17 (18.3) |
| Sore throat | ||||||
| Delta predominant period | 85 (18.6) | N/A | 3 (4.1) | 5 (5.7) | 26 (18.3) | 51 (38.1) |
| Omicron predominant period | 89 (22.9) | N/A | 0 (0.0) | 3 (4.5) | 30 (25.9) | 56 (60.2) |
| Cough | ||||||
| Delta predominant period | 215 (46.9) | 6 (30.0) | 26 (35.1) | 40 (45.5) | 60 (42.3) | 83 (61.9) |
| Omicron predominant period | 191 (49.1) | 10 (37.0) | 50 (58.1) | 30 (44.8) | 54 (46.6) | 47 (50.5) |
| Wheezing | ||||||
| Delta predominant period | 6 (1.3) | N/A | 2 (2.7) | 4 (4.5) | 0 (0.0) | 0 (0.0) |
| Omicron predominant period | 11 (2.8) | N/A | 6 (7.0) | 4 (6.0) | 1 (0.9) | 0 (0.0) |
| Chest pain | ||||||
| Delta predominant period | 8 (1.7) | N/A | 0 (0.0) | 0 (0.0) | 2 (1.4) | 6 (4.5) |
| Omicron predominant period | 2 (0.5) | N/A | 0 (0.0) | 1 (1.5) | 0 (0.0) | 1 (1.1) |
| Fatigue | ||||||
| Delta predominant period | 81 (17.7) | N/A | 6 (8.1) | 2 (2.3) | 17 (12.0) | 56 (41.8) |
| Omicron predominant period | 49 (12.6) | N/A | 2 (2.3) | 7 (10.4) | 20 (17.2) | 20 (21.5) |
| Headache | ||||||
| Delta predominant period | 72 (15.7) | N/A | 1 (1.4) | 3 (3.4) | 15 (10.6) | 53 (39.6) |
| Omicron predominant period | 46 (11.8) | N/A | 0 (0.0) | 5 (7.5) | 16 (13.8) | 25 (26.9) |
| Alteration of consciousness | ||||||
| Delta predominant period | 4 (0.9) | 0 (0.0) | 0 (0.0) | 2 (2.3) | 1 (0.7) | 1 (0.7) |
| Omicron predominant period | 8 (2.1) | 0 (0.0) | 0 (0.0) | 1 (1.5) | 5 (4.3) | 2 (2.2) |
| Seizures | ||||||
| Delta predominant period | 9 (2.0) | 0 (0.0) | 3 (4.1) | 2 (2.3) | 3 (2.1) | 1 (0.7) |
| Omicron predominant period | 24 (6.2) | 0 (0.0) | 6 (7.0) | 9 (13.4) | 9 (7.8) | 0 (0.0) |
| Diarrhea | ||||||
| Delta predominant period | 38 (8.3) | 0 (0.0) | 9 (12.2) | 7 (8.0) | 10 (7.0) | 12 (9.2) |
| Omicron predominant period | 22 (5.7) | 1 (3.7) | 5 (5.8) | 2 (3.0) | 11 (9.5) | 3 (3.2) |
| Vomiting | ||||||
| Delta predominant period | 39 (8.5) | 2 (10.0) | 5 (6.8) | 7 (8.0) | 9 (6.3) | 16 (11.9) |
| Omicron predominant period | 65 (16.7) | 2 (7.4) | 10 (11.6) | 13 (19.4) | 32 (27.6) | 8 (8.6) |
| Dysgeusia | ||||||
| Delta predominant period | 28 (6.1) | N/A | 0 (0.0) | 1 (1.1) | 9 (6.3) | 18 (13.4) |
| Omicron predominant period | 3 (0.8) | N/A | 0 (0.0) | 0 (0.0) | 1 (0.9) | 2 (2.2) |
| Olfactory dysfunction | ||||||
| Delta predominant period | 26 (5.7) | N/A | 0 (0.0) | 0 (0.0) | 8 (5.6) | 18 (13.4) |
| Omicron predominant period | 0 (0.0) | N/A | 0 (0.0) | 0 (0.0) | 0 (0.0) | 0 (0.0) |
| Arthralgia/myalgia | ||||||
| Delta predominant period | 25 (5.5) | N/A | 0 (0.0) | 0 (0.0) | 2 (1.4) | 23 (17.2) |
| Omicron predominant period | 12 (3.1) | N/A | 0 (0.0) | 1 (1.5) | 4 (3.4) | 7 (7.5) |
| Rash | ||||||
| Delta predominant period | 9 (2.0) | 1 (5.0) | 5 (6.8) | 2 (2.3) | 1 (0.7) | 0 (0.0) |
| Omicron predominant period | 9 (2.3) | 1 (3.7) | 2 (2.3) | 3 (4.5) | 2 (1.7) | 1 (1.1) |
SpO2, saturated oxygen in arterial blood.
Subjective symptoms in children under 3 months were not applicable (N/A) because they had difficulty describing them.
Symptom frequencies by age between the Delta and Omicron variant predominant periods were compared using the Fisher exact test for categorical variables and Mann-Whitney U test for continuous variables; items with P < 0.05 are in bold.