Hospitalized children with COVID-19 infection during large outbreak of SARS-CoV-2 Omicron strain: a retrospective study in Chaozhou, Guangdong, China

Figures & data

Figure 1. The number of daily admitted cases in the paediatric department.

Table 1. Demographic and clinical characteristics of 286 children with SARS-CoV-2 Omicron infection.

Characteristics	All patients	Mild	Moderate	Severe/critical	P1	P2	P3
Cases	286 (100)	138 (48.3)	126 (44.0)	22 (7.7)
Gender
Male	175 (61.2)	85 (61.6)	78 (61.9)	12 (54.5)	.959	.530	.514
Female	111 (38.8)	53 (38.4)	48 (38.1)	10 (45.5)
Age, years at admission (median, IQR)	1.6 (0.6–2.9)	1.7 (0. 7–3.0)	1.3 (0.5–2.4)	2.6 (0.3–7.3)	.039	.188	.036
<3	218 (76.2)	102 (73.9)	104 (82.5)	12 (54.5)	.091	.062	.009
≥3	68 (23.8)	36 (26.1)	22 (17.5)	10 (45.5)
Vaccination^c (age ≥ 3 years)	45 (66.2)	22 (61.1)	16 (72.7)	7 (70.0)	.366	.723	>.999
Length of hospital stay, day (median, IQR)a	3 (3.0–5.0)	3 (2.0–4.0)	4 (3.0–5.3)	7.0 (4.5–9.3)	<.001	.001	.009
Fever or not
Fever	256 (89.5)	130 (94.2)	111 (88.1)	15 (68.2)	.094	.001	.024
Peak temperature ≥39 °C	174 (60.8)	87 (66.9)	80 (72.1)	7 (46.7)	<.001	.495	.071
Fever ≥ 5 d	35 (12.2)	11 (8.1)	22 (19.8)	2 (13.3)	.014	.184	>.999
Upper respiratory tract presentation
Cough	225 (78.7)	101 (73.1)	108 (85.7)	16 (72.7)	.012	>.999	.205
Sore throat	18 (6.3)	8 (5.7)	9 (7.1)	1 (4.5)	.656	>.999	>.999
Antiadoncus	140 (49.0)	65 (47.1)	62 (49.2)	13(59.0)	.717	.296	.216
Runny nose	92 (32.2)	53 (38.4)	36 (28.5)	3 (13.6)	.091	.024	.142
Nasal stuffiness	52 (18.2)	28 (20.2)	22 (17.4)	2 (9.0)	.558	.375	.531
Acute laryngitis	50 (17.5)	2 (1.4)	45 (35.7)	3 (13.6)	<.001	.019	.041
Dyspnoea	54 (18.9)	15 (10.8)	33 (26.1)	6 (27.2)	.001	.046	.901
Gastrointestinal symptoms
Vomiting/nausea	47 (16.4)	21 (15.2)	20 (15.8)	6 (27.2)	.883	.216	.225
Diarrhoea	31 (10.8)	12 (8.6)	16 (12.6)	3 (13.6)	.291	.437	>.999
Poor appetite	185 (64.7)	86 (62.3)	80 (63.4)	19 (86.3)	.844	.027	.035
Febrile convulsions	96 (33.6)	53 (38.4)	30 (23.8)	13 (59.0)	.011	.067	.001
Abnormalities on chest CT	46/64 (71.9)	0/5 (0)	35/42 ((83.3)	11/17 (64.7)	.001	.035	.166
Scattered inflammation shadowing	45/64 (70.3)	0/5 (0)	34/42 (81.0)	11/17 (64.7)	.001	.035	.197
Lung consolidation	13/64 (20.3)	0/5 (0)	7/42 (16.7)	6/17 (35.3)	>.999	.266	.166
Abnormalities on brain CT	3/35 (8.6)	0/9 (0)	0/13 (0)	3/13 (23.1)	–	.280	.232
Abnormalities on brain MRI	6/9 (66.7)	0/0 (0)	0/1 (0)	6/8 (83.3)	–	–	.333
Comorbidities	13 (4.5)	4 (2.9)	5 (4.0)	4 (18.2)	.741	.013	.028
Type 1 diabetes	2 (0.7)	0 (0)	0 (0)	2 (9.1)
Congenital heart disease	2 (0.7)	0 (0)	2 (1.6)	0 (0)
Others^d	9 (3.1)	4 (2.9)	3 (2.4)	2 (9.1)
Co-infection
Other respiratory virusese	6/113 (5.3)	3/43 (7.0)	2/56 (3.6)	1/14 (7.1)	.650	>.999	.494
MIS-Cb	8 (2.8)	0 (0)	0 (0)	8 (36.4)	–	<.001	<.001
Medical treatment
Antibiotics	97 (33.9)	25 (18.1)	55 (43.7)	17 (77.3)	<.001	<.001	.004
Corticosteroids	136 (47.6)	38 (27.5)	81 (64.3)	17 (77.3)	<.001	<.001	.235
Traditional Chinese medicine	84 (29.4)	39 (28.3)	42 (33.3)	3 (13.6)	.372	.148	.064
Immunoglobulin	18 (6.3)	1 (0.7)	3 (2.4)	14 (63.6)	.351	<.001	<.001
Oxygen inhalation	54 (18.8)	5 (3.6)	28 (22.2)	21 (95.5)	<.001	<.001	<.001
Nasal prong oxygen	52 (18.2)	5 (3.6)	28 (22.2)	19 (86.4)
Mechanical ventilation	2 (0.6)	0 (0)	0 (0)	2 (9.1)
Outcome
Cure/discharge	285 (99.7)	138 (100)	126 (100)	21 (95.5)	–	.137	.149
Death in hospital	1 (0.3)	0 (0)	0 (0)	1 (4.5)

P1: p values of mild vs. moderate; P2: p values of mild vs. severe/critical; P3: p values of moderate vs. severe/critical.

Data are n (%) except for age and length of hospital stay, where N is the total number of patients with available data.

^a Excluding four patients who have not cured and discharged from the hospital. (–) Not enough data for statistical analyses.

^b MIS-C: multisystem inflammatory syndrome in children.

^c Children without documented receipt of any COVID-19 vaccine dose before hospitalization were considered to be unvaccinated, vaccination status was confirmed from children’s parents.

^d Epilepsy (three cases), hyperthyroidism (one case), autoimmune anaemia (one case), cerebral palsy (one case), gastrointestinal bleeding (one case), adrenocortical hypofunction (one case) and autoimmune encephalitis (one case).

^e Parainfluenza virus (two cases), respiratory syncytial virus (one case), rhinovirus (two cases) and adenovirus (one case).

Figure 2. Comparison of the main laboratory indices between mild, moderate, severe and critical groups.

Table 2. The main laboratory findings of children with SARS-CoV-2 Omicron infection: mild, moderate, severe and critical groups.

Laboratory finding	All patients (n = 286)	Mild (n = 138)	Moderate (n = 126)	Severe/critical (n = 22)	P1	P2	P3
White blood cell (×10^9/L)	9.64 ± 0.30	8.51 ± 0.31	10.57 ± 0.53	11.44 ± 1.33	.001	.042	.522
Reduced	31/280 (11.1%)	15/136 (11.0%)	14/122 (11.5%)	2/22 (9.1%)	.910	>.999	>.999
Elevated	50/280 (17.9%)	14/136 (10.3%)	28/122 (23.0%)	8/22 (36.4%)	.006	.003	.181
Lymphocyte (×10^9/L)	2.64 ± 0.15	2.18 ± 0.16	3.24 ± 0.27	2.15 ± 0.41	.001	.940	.101
Reduced	166/280 (59.3%)	93/136 (68.4%)	59/122 (48.4%)	14/22 (63.6%)	.001	.659	.187
Haemoglobin (g/L)	119.07 ± 0.67	120.43 ± 0.88	117.87 ± 0.93	117.36 ± 4.12	.047	.475	.906
Reduced	23/280 (8.2%)	10/136 (7.4%)	7/122 (5.7%)	6/22 (27.3%)	.602	.013	.005
Platelet (<150 × 10^9/L)	260.04 ± 5.30	257.09 ± 7.47	264.80 ± 8.23	251.91 ± 18.90	.488	.797	.540
Reduced	51/280 (18.2%)	23/136 (16.9%)	23/122 (18.9%)	5/22 (22.7%)	.684	.717	.897
C-reactive protein (≥8 mg/L)	108/281 (38.4%)	51/136 (37.5%)	48/123 (39.0%)	9/22 (40.9%)	.801	.760	.868
Procalcitonin (≥0.10 ng/mL)	197/273 (72.2%)	94/130 (72.3%)	86/121 (71.1%)	17/22 (77.3%)	.828	.627	.551
Interleukin-6 (>7 ng/L)	79/98 (80.6%)	35/46 (76.1%)	38/44 (86.4%)	6/8 (75.0%)	.213	>.999	.774
D-dimer (≥0.50 μg/mL)	26/50 (52%)	11/23 (47.8%)	5/14 (35.7%)	10/13 (76.9%)	.471	.089	.031
Alanine aminotransferase (U/L)	26.53 ± 0.91	26.07 ± 1.13	24.50 ± 1.10	40.86 ± 6.42	.323	.033	.020
Elevated	14/283 (4.9%)	7/137 (5.1%)	1/124 (0.8%)	6/22 (27.3%)	.098	.002	<.001
Aspartate aminotransferase (U/L)	46.39 ± 1.94	43.91 ± 1.48	42.21 ± 1.12	85.41 ± 21.09	.367	.063	.053
Elevated	32/283 (11.3%)	14/137 (10.2%)	8/124 (6.5%)	10/22 (45.5%)	.274	<.001	<.001
Lactose dehydrogenase (U/L)	327.67 ± 4.78	315.70 ± 4.95	328.07 ± 5.78	399.41 ± 39.28	.103	.046	.086
Elevated	43/281 (15.3%)	13/136 (9.6%)	22/123 (17.9%)	8/22 (36.4%)	.050	.002	.092
Creatine kinase (U/L)	177.62 ± 11.90	157.30 ± 8.56	161.99 ± 14.29	390.55 ± 110.57	.774	.048	.053
Elevated	48/281 (17.1%)	20/136 (14.7%)	19/123 (15.4%)	9/22 (40.9%)	>.868	.008	.013
Creatine kinase-MB (U/L)	22.20 ± 0.70	20.97 ± 0.67	21.63 ± 0.74	33.05 ± 6.43	.510	.076	.092
Elevated	75/281 (26.7%)	28/136 (20.6%)	37/123 (30.1%)	10/22 (45.5%)	.078	.011	.156
Creatinine (μmol/L)	38.52 ± 0.83	38.46 ± 0.98	37.07 ± 0.94	46.95 ± 6.85	.311	.233	.167
Elevated	114/281 (40.6%)	51/136 (37.5%)	56/123 (45.5%)	7/22 (31.8%)	.190	.608	.232

P1: p values of mild vs. moderate; P2: p values of mild vs. severe/critical; P3: p values of moderate vs. severe/critical.

Data are n (%) and mean (SE). Elevated means over the upper limit of the normal range and reduced means below the lower limit of the normal range. The normal limits: white blood cell, 0 ≤ age < 6 months: 4.3–14.2 (×10⁹/L), 6 months ≤ age < 1 years: 4.8–14.6 (×10⁹/L), 1 years ≤ age < 2 years: 5.1–14.1 (×10⁹/L), 2 years ≤ age < 6 years: 4.4–11.9 (×10⁹/L), 6 years ≤ age < 13 years: 4.3–11.3 (×10⁹/L); lymphocyte, 0 ≤ age < 6m: 2.4–9.5 (×10⁹/L), 6 months ≤ age < 1 years: 2.5–9.0 (×10⁹/L), 1 years ≤ age < 2 years: 2.4–8.7 (×10⁹/L), 2 years ≤ age < 6 years: 1.8–6.3 (×10⁹/L), 6 years ≤ age < 13 years: 1.5–4.6 (×10⁹/L); haemoglobin, 0 ≤ age < 6 months: 97–183 (g/L), 6 months ≤ age < 1 years: 97–141 (g/L), 1 years ≤ age < 2 years: 107–141 (g/L), 2 years ≤ age < 6 years: 112–149 (g/L), 6 years ≤ age < 13 years: 118–156 (g/L); platelet: 0 ≤ age < 6 months: 183–614 (g/L), 6 months ≤ age < 1 years: 190–579 (g/L), 1 years ≤ age < 2 years: 190–524 (g/L), 2 years ≤ age < 6 years: 188–472 (g/L), 6 years ≤ age < 13 years: 167–453 (g/L); C-reactive protein, <8.00 (mg/L); procalcitonin, <0.10 (ng/mL); interleukin-6, 0–7 (ng/L); D-dimer: <0.50 (μg/ml); alanine transaminase, 0 ≤ age < 1 years: 8–71 (U/L), 1 years ≤ age < 2 years: 8–42 (U/L), 2 years ≤ age < 13 years: 7–30 (U/L); aspartate transaminase, 0 ≤ age < 1 years: 21–80 (U/L), 1 years ≤ age < 2 years: 22–59 (U/L), 2 years ≤ age < 13 years: 14–44 (U/L); lactose dehydrogenase: 0 ≤ age < 1d: male 0–248 (U/L), female 0–247 (U/L), 1 d ≤ age < 1 months: male 125–735 (U/L), female 145–765 (U/L), 1 months ≤ age < 1 years: male 170–450 (U/L), female 190–420 (U/L), 1 years ≤ age < 13 years: male 155–345 (U/L), female 165–395 (U/L); creatine kinase, 0 ≤ age < 1d (U/L), 1 d ≤ age < 5 d: 26–700 (U/L), 5 d ≤ age < 6 months: 26–330 (U/L), 6 months ≤ age < 13 years: 26–229 (U/L); creatine kinase-MB, 0–24 (U/L); creatinine, 0 ≤ age < 2 years: 13–33 (μmol/L), 2 years ≤ age < 6 years: 19–44 (μmol/L), 6 years ≤ age < 13 years:27–66 (μmol/L); IVIG: intravenous immunoglobulin.

Data availability statement

All data generated or analysed during this study are included in this article. Further enquiries can be directed to the corresponding author.