Since the first patients infected with COVID–19 of Shenzhen was confirmed, the government immediately took a series of measures such as hospital confinement, traffic screening, extending vacations, postponing the reopening time of schools, offering free nucleic acid testing, 100% closed community management, etc.,, Figure–1A. On February 21st, the total number of discharged patients exceeded that of hospitalized patients for the first time, Figure–1B. The daily updated number of close contacts and hospitalized patients in critical and severe conditions continued to decline, Figure 1C and D.
All confirmed patients were treated at the Third People’s Hospital of Shenzhen. Among the 417 local confirmed cases, there were 198(47.5%) male and 219(52.5%) female. The ages were ranged 1–86 years old, averaged at 45.4±17.7 years old, the median age and interquartile range was 47(34–60) years old, Figure 2A. All the numbers were significantly less than previous reports 5,6. The number of patients has mild, normal, severe and critical symptoms was 16(3.8%), 309(74.1%), 73 (17.5%) and 19 (4.6%), respectively. All of the three fatalities were males over 60 years old, and the case fatality ratio (0.72%, 3/417) was equal to the national average 6. To facilitate statistics, we combined mild and normal patients into non-severe group, and severe and critical patients into severe group.
Age, gender, exposure to source of transmission within 14 days and basic diseases are major risk factors for severe patients, Table 1. The average ages of severe patients were over 16 years elder than non-severe patients (P<0.001). The ratio of patients under 18 years old in Shenzhen reached 7.2%, which was significantly higher than the national level, fortunately, there were no severe patients in children, the proportion of severe patients rapidly increased with age, nearly half (48.9%) of elders over or equal to 66 years old were in severe conditions.
The proportion of severe patients in male were almost twice than in female (64.1% vs 35.9, P<0.001). Over half (53.2%) of the 417 patients has Wuhan exposure history in the last 14 days before their self-narrative onset day. The median onset date for patients with Wuhan exposure was 5 days’ earlier than those with no Wuhan exposure (January 24th vs January 29th), Figure 2B. Twenty-two out of the 417 cases have no clear contact history (never left Shenzhen, or contact any infected patient), it suggests that there’s risk of active vital transmission in Shenzhen. Patients who exposed to Wuhan before onset within 14 days has higher severe proportion than those with no Wuhan exposure (27.5% vs 15.9%, P<0.01), Table 1.
Patients carried at least on basic diseases were under higher risks too (36.4% vs 16%, P<0.001). Metabolic diseases were the most common basic diseases carried by the confirmed cases. Patients carried with hypertension, diabetes, hyperlipidemia, cardiovascular and cerebrovascular diseases and malignant tumors have higher risks of developing severe condition. Among that, the ratio of severe was highest (60.7%) in patients with cardiovascular and cerebrovascular diseases, Table 1.
Obvious family clusters were observed in the 417 confirmed cases of Shenzhen involving 84 clusters totally 229 (54.9%) infected patients, it is much higher than in previous studies 7,8. The first familial cluster was shown in Figure 2C, case 5 was the first medical patients in Guangdong province and become the key person to find out the first familial cluster; case 1 was the first confirmed patients in Guangdong, and died on February 16. In addition to case 5, the other four have a history of exposure to Wuhan. The largest local community cluster of cases was shown in Figure 2D, all the 9 cases have no Wuhan exposure history.
Totally of 368 patients have been discharged from the hospital by the end the March 7th, the basic information was shown in Table 1. The proportion of age, gender, exposure history and basic diseases were similar to the total 417 confirmed patients.
As shown in Table 2, the days of hospitalization showed no significant difference between men and women. Patients with Wuhan exposure history seemed to need more time of hospitalization, but there was no significant difference compared to those with no exposure. Age was a main influence factor for discharge. Patients ≤45 years old takes less time (P<0.001) from onset to discharge than elder ones (≥46 years old). Pearson test showed that ages of patients was positively correlated with the time from onset to admission (0.125, P = 0.017), admission to discharge (0.273, P = 0.000) and onset to discharge (0.301, P = 0.000). The patients carried at least one basic disease took longer time of hospitalization than those with no basic diseases (P<0.05). And the patients in severe conditions spend more time in hospital than those in non-severe conditions (P<0.001). Besides, we noticed that patients in severe conditions went to hospital later than those in non-severe conditions (P<0.05), and that might be partly influenced the progression of disease.