General information on enrolled patients
A total of 461 subjects were enrolled in this study and divided into 3 groups, namely 2022 shanghai COVID-19 group (SH-C); 2022 shanghai non-COVID-19 group (SH-N) and 2020 wuhan COVID-19 group (WH-C). The general conditions of the three groups of subjects are shown in Table 1. The mean age of WH-C was the oldest, and the mean age of SH-N was the youngest, at 60.4 and 42.7 years, respectively. There was no significant difference in the ratio of males to females among the 3 groups. The etiology of the 3 groups was significantly different, namely Omicron variant, respiratory infection and SARS-CoV-2. In terms of the vaccination rate of the COVID-19 the SH-C group was significantly lower than the SH-N group (49.65% vs. 72.73%), which fully shows that the vaccination of the COVID-19 can prevent the infection of the Omicron variant.
Table 1
General information of included population.
| SH-C, n = 144 | SH-N, n = 144 | WH-C, n = 173 |
Age, y | | | |
| 57.5 ± 22.4 | 42.7 ± 18.6 | 60.4 ± 12.4 |
Gender, F/M | | | |
| 81/63 | 77/67 | 72/101 |
Cause of disease | | | |
| Omicron | respiratory infection | SARS-CoV-2 |
Vaccination rate | | | |
| 49.65% | 72.73% | 0 |
SH-C, shanghai COVID-19 group; SH-N, non-COVID-19 group (due to respiratory infection); WH-C, wuhan COVID-19 group (2020). |
The Difference Between The Shanghai Epidemic And The Wuhan Epidemic
COVID-19 outbreak in Shanghai is fundamentally different from the outbreak in Wuhan two years ago. Among the hospitalized patients, 34.0% of the patients in SH-C group were less than 50 years old, which was significantly higher than that in WH-C group. The difference between men and women in different periods is not obvious. The mean body temperature of SH-C group was 37.5℃, which was lower than 38.0 of WH-C group, and the difference was statistically significant (P < 0.001). In addition, the incidence rates of leukocyte, pneumonia and symptom in SH-C group were higher than those in WH-C group, which was due to the larger proportion of basic illness (Table 2). Most of the patients who come to the fever clinic are those with fever or other symptoms of respiratory tract infection, and those with COVID-19 infection who have no obvious symptoms and are found during screening will be sent to mobile cabin hospital. The underlying disease of the patient often increases the impact of the COVID-19 on health.
Table 2
Comparison of hospital admissions of patients with COVID-19 between in Shanghai and in Wuhan.
Factors | SH-C, n = 144(%) | WH-C, n = 173(%) | P value |
age | | | < 0.001 |
| < 50 | 49(34.0) | 29(16.8) | |
| 50–60 | 19(13.2) | 45(26.0) | |
| ≥ 60 | 76(52.8) | 99(57.2) | |
gender | | | 0.702 |
| female | 81(56.3) | 101(58.4) | |
| male | 63(43.8) | 72(41.6) | |
body temperature (℃) | | | < 0.001 |
| | 37.5 ± 1.0 | 38.0 ± 0.9 | |
leukocyte | | | 0.007 |
| | 6.92 ± 2.85 | 6.02 ± 2.88 | |
pneumonia | | | < 0.001 |
| no | 81(56.3) | 148(85.5) | |
| yes | 63(43.8) | 25(14.5) | |
symptom | | | < 0.001 |
| mild | 61(42.4) | 104(60.1) | |
| severe | 83(57.6) | 69(39.9) | |
basic illness | | | - |
| hypertension | 31(21.5) | 26(15.0) | |
| cerebrovascular | 16(11.1) | 12(6.9) | |
| diabetes | 14(9.7) | 13(7.5) | |
| heart disease | 12(8.3) | 5(2.9) | |
| post-operative | 6(4.1) | 7(4.0) | |
| liver disease | 4(2.7) | 5(2.9) | |
| kidney disease | 4(2.7) | 2(1.1) | |
| autoimmune disease | 1(0.7) | 0(0) | |
SH-C, patients with COVID-19 in Shanghai on 2022; WH-C, patients with COVID-19 in Wuhan on 2020. |
Differences Between Covid-19 And Respiratory Infections
Comparative analysis was used for patients with COVID-19 related pneumonia and patients with respiratory tract infection in Shanghai. We found that there was no significant difference in body temperature between patients with COVID-19 related pneumonia and respiratory tract infections (P = 0.099). In terms of WBC and CRP indicators, the patients with the COVID-19 in Shanghai were lower than those with respiratory tract infection, and the difference was statistically significant (P < 0.05). There was no significant difference in N%, L%, monocytes, eosinophils, RBC, HB, PLT, etc. between patients with COVID-19 and with respiratory tract infection (P > 0.05). However, monocytes were higher in patients with COVID-19 than in patients with respiratory tract infection (P < 0.05) (Fig. 2).
Analysis Of Risk Factors For Pneumonia Caused By Omicron
For the analysis of the influencing factors of Omicron leading to COVID-19 related pneumonia, we use the internal control method. Among the 144 positive patients with COVID-19 collected, there were 63 pneumonia patients and 81 infected patients. Univariate analysis showed that age over 60 years was a risk factor for COVID-19 related pneumonia [HR = 14.62 (5.49–38.92), P < 0.001]. Vaccination was a protective factor [HR = 0.24 (0.12–0.49), P < 0.001], and people with underlying diseases are also more likely to develop pneumonia [HR = 5.29 (2.58–10.85), P < 0.001]. No significant difference in body temperature was observed between pneumonia patients and infected patients (P > 0.05). However, in terms of WBC and CRP indicators, the abnormal rate of pneumonia patients was significantly higher than that of the control group (P < 0.05) (Table 3).
Table 3
Comparison of factors related to pneumonia caused by the epidemic of COVID-19 on Shanghai in 2022.
Factors | non-pneumonia, n = 81 | pneumonia, n = 63 | Univariate analysis HR (95% CI) | P value |
age | | | | |
| < 50 | 43 | 6 | 1 | |
| 50–60 | 13 | 6 | 3.31 (0.91–12.02) | 0.069 |
| ≥ 60 | 25 | 51 | 14.62 (5.49–38.92) | < 0.001 |
gender | | | | |
| female | 49 | 32 | 1 | |
| male | 32 | 31 | 1.48 (0.76–2.88) | 0.768 |
vaccine | | | | |
| no | 28 | 42 | 1 | |
| yes | 52 | 19 | 0.24 (0.12–0.49) | < 0.001 |
basic illness | | | | |
| no | 55 | 18 | 1 | |
| yes | 26 | 45 | 5.29 (2.58–10.85) | < 0.001 |
body temperature | | | | |
| normal | 49 | 31 | | |
| abnormal | 32 | 32 | - | 0.176* |
WBC | | | | |
| normal | 71 | 48 | | |
| abnormal | 5 | 15 | - | 0.004* |
monocytes | | | | |
| normal | 32 | 34 | | |
| abnormal | 44 | 29 | - | 0.163* |
CRP | | | | |
| normal | 54 | 28 | | |
| abnormal | 22 | 35 | - | 0.001* |
* Chi-square test results; normal range: body temperature: <37.3℃; WBC, White blood cell count: 3.5–9.5*109/L; monocytes: 3–10%; CRP, C reactive protein: 0-10mg/L. |