Study on the correlation between molecular characteristics of SARS-CoV-2 and its epidemiology and clinical manifestations in Lu’an city

Table 1 Comparison of clinical characteristics among coronavirus disease 2019 cases in Lu’an city (2020-2022)

Item	2020		2021		2022		Total		Statistics of different years
	n	%	n	%	n	%	n	%	χ2	P value
Cough	47	90.38 (47/52)	5	31.25 (5/16)	9	39.13 (9/23)	61	67.03 (61/91)	30.205	< 0.001
Fever	47	90.38 (47/52)	4	25.00 (4/16)	8	36.36 (8/22)	59	65.56 (59/90)	34.154	< 0.001
Chest tightness/chest discomfort	22	47.83 (22/46)	0	0 (0/8)	0	0 (0/15)	22	31.88 (22/69)	16.149	< 0.001
Chills	1	8.33 (1/12)	0	0 (0/1)	1	20.00 (1/5)	2	11.11 (2/18)	0.619	0.734
Feeling cold/rigors	4	26.67 (4/15)	4	25.00 (4/16)	0	0 (0/4)	8	22.86 (8/35)	1.350	0.509
Mild fatigue	6	31.58 (6/19)	0	0 (0/1)	2	40.00 (2/5)	8	32.00 (8/25)	0.619	0.734
Headache	3	17.65 (3/17)	3	33.33 (3/9)	0	0 (0/12)	6	15.79 (6/38)	4.377	0.112
Chest pain	2	9.52 (2/21)	0	0 (0/14)	0	0 (0/23)	2	3.45 (2/58)	3.650	0.161
Vomiting	4	12.50 (4/32)	1	6.25 (1/16)	0	0 (0/23)	5	7.04 (5/71)	2.923	0.232
Nausea	8	22.22 (8/36)	1	6.25 (1/16)	1	4.35 (1/23)	10	13.33 (10/75)	3.981	0.137
Abdominal pain	4	14.29 (4/28)	0	0 (0/16)	1	4.35 (1/23)	5	7.46 (5/67)	3.501	0.174
Diarrhea	12	37.50 (12/32)	5	31.25 (5/16)	0	0 (0/23)	17	23.94 (17/71)	10.939	0.004
Convulsion/impaired consciousness	1	2.00 (1/50)	0	0 (0/16)	0	0 (0/23)	1	11.24 (10/89)	0.789	0.674
Poor mental state, appetite, or sleep	24	46.15 (24/52)	8	50.00 (8/16)	3	13.04 (3/23)	35	38.46 (35/91)	8.478	0.014
Lymphadenopathy	0	0 (0/52)	0	0 (0/16)	0	0 (0/23)	0	0 (0/91)	-	-
CT findings/CT abnormalities	47	90.38 (47/52)	12	80.00 (12/15)	10	47.62 (10/21)	69	78.41 (69/88)	16.187	< 0.001
Pharyngeal redness	27	51.92 (27/52)	10	62.50 (10/16)	12	57.14 (12/21)	49	55.06 (49/89)	0.602	0.74
Tonsillar enlargement	1	1.92 (1/52)	1	6.25 (1/16)	10	43.48 (10/23)	12	13.19 (12/91)	24.870	< 0.001
Blood oxygen saturation	30	81.08 (30/37)	2	12.50 (2/16)	0	0 (0/23)	32	42.11 (32/76)	45.538	< 0.001
Sore throat	4	22.22 (4/18)	3	50.00 (3/6)	7	63.64 (7/11)	14	40.00 (14/35)	5.181	0.075
Brudzinski’s sign	0	0 (0/52)	0	0 (0/16)	0	0 (0/22)	0	0 (0/90)	-	-
Kernig’s sign	0	0 (0/52)	0	0 (0/16)	0	0 (0/22)	0	0 (0/90)	-	-
Babinski’s sign	0	0 (0/52)	0	0 (0/16)	0	0 (0/22)	0	0(0/90)	-	-
CRP	28	60.87 (28/46)	7	43.75 (7/16)	4	23.53 (4/17)	39	49.37 (39/79)	7.177	0.028
Myalgia	1	3.03 (1/33)	0	0 (0/14)	0	0 (0/16)	1	15.87 (10/63)	0.924	0.63
Elevated WBC count	2	3.85 (2/52)	3	18.75 (3/16)	0	0 (0/18)	5	5.81 (5/86)	6.368	0.014
Decreased WBC count	6	11.54 (6/52)	1	6.25 (1/16)	3	16.67 (3/18)	10	11.63 (10/86)	0.895	0.639
Clinical classification									15.100	0.001
Asymptomatic	0	0 (0/52)	3	18.75 (3/16)	5	21.74 (5/23)	8	8.79 (8/91)	11.800	0.003
Mild	5	9.62 (5/52)	2	12.5 (2/16)	8	34.78 (8/23)	15	16.48 (15/91)	7.561	0.023
Moderate	41	78.85 (41/52)	11	68.75 (11/16)	10	43.48 (10/23)	62	68.13 (62/91)	11.069	0.004
Severe	6	11.54 (6/52)	0	0 (0/16)	0	0 (0/23)	6	6.59 (6/91)	4.818	0.09

Older age was associated with a higher risk of severe coronavirus disease 2019 (odds ratio = 1.05, 95 % confidence interval: 1.04-1.06). No significant association was observed between gender and severe case rate (χ² = 1.276, P = 0.259). Patients with underlying diseases (e.g., hypertension, diabetes, or liver impairment) had a significantly higher severe case rate compared to those without χ² = 12.213, P < 0.01). Comparison of clinical classification (mild/moderate/severe) between the combined 2020-2021 cohort and the 2022 cohort was performed using Fisher’s exact test (χ² = 15.100, P < 0.01). CT: Computed tomography; CRP: C-reactive protein; WBC: White blood cell.