As a designated general hospital for the treatment of COVID-19 in Shenzhen, the General Hospital of Shenzhen University is responsible for the screening and treatment work of suspected cases. It differs from infectious diseases specialist hospitals in the following ways: 1. There are fewer medical personnel specialized in infectious diseases, and weaker professional and technical strength; 2. There is a lack of treatment areas for infectious cases, and limited reception for a large number of patients with severe infectious diseases; 3. The outpatient and inpatient population of in a general hospital are complex and prone to cross-infection. On the basis of the above characteristics, the prevention and treatment work of our hospital was mainly focused on the confirming of suspected COVID-19 cases and the treatment of patients with mild and common symptoms before diagnosis. The diagnosis and treatment should be classified and separated reasonably according to the diagnosis and treatment process in Fig. 1, and each diagnosis and treatment area should be utilized efficiently to ensure that each suspected patient was individually under medical observation in a single room until diagnosis was ruled out. By now, a total of 28 cases of COVID-19 patients have been confirmed in our hospital, with everyone having been sent to the specialized hospitals of infectious diseases for further treatment. There was no infection among medical personnel, no cross-infection among the patients in the hospital, and no misdiagnosis or missed diagnosis of COVID-19, which had little impact on the diagnosis and treatment of the other patients in the hospital.
The population distribution of the patients in the group ranged from infants to the elderly, with a median age of 35 years old, which were mainly young adults aged 15 to 60 years old. Most of them were employees in the company who were always required to go on a business trip frequently to many places. No patients in this group were in combination with severe chronic diseases. Among the 28 confirmed cases, only one was imported from aboard, which was due to the epidemic prevention policy. The inbound flights were reduced and prevention and control measures were strengthened during the outbreak. 17 cases had a clear travel history in the epidemic areas, with Wuhan, Hubei province being the most, followed by the other regions of Hubei province, which was related to the fact that Wuhan had the most COVID-19 cases and the most severe epidemic status of COVID-19 in China. Different from the fact reported by Liaocheng Hospital of Infectious Disease that only 2 of the 26 cases there had travelling and living history in Wuhan,it was considered that this may be related to the fact that Shenzhen was one of the first-tier cities in China with a large population mobility. There were 10 cases of COVID-19 with travelling history and close contacts in the epidemic areas, and 7 cases with only close contact history, indicating the characteristics of human-to-human transmission of COVID-19, which was same with the human-to-human transmission pattern of COVID-19 in Wuhan reported earlier by Julien Riou on 30 January 2020. The majority of close contact group were parents and spouses, which indicated that COVID-19 might be easily transmitted among family members. Besides, all of the 6 clustered cases involved in this paper occurred in families, suggesting that home quarantine was one of the important means of COVID-19 prevention and control. And there was no severe case in this group, and most of them were patients with mild and common symptoms, which was related to the prevention and control of the General Hospital that only suspected cases were screened, while the severe cases were mainly treated in specialized hospitals of infectious diseases.
The time period from leaving the epidemic area to the attack and the time period from close contacting to the attack were analyzed as 0–20 days and 0–14 days in this paper, respectively. Therefore, we required that people with travel and close contact history in the epidemic areas should be quarantined for at least 14 days. With the development of the outbreak, the improvement of prevention and control measures and treatment experience, the amount of cases dropped from 22 during January - February, 2020 to 6 during March- April, 2020, with a trend from common cases to asymptomatic cases, which reflected the results of the previous prevention and control work and suggested that the focus of prevention and control should be transferred to asymptomatic infected cases. Therefore, it is one of the important prevention and control measures to identify infected cases by improving the detection capacity of SARS-CoV-2 RNA.
The first symptom of nearly half of the patients in the group was fever, and high fever was rare. Others were mainly respiratory symptoms, and diarrhea symptoms in a few cases. No specific symptoms of COVID-19 were observed, making it difficult to differentiate from the influenza. there was no abnormality in the count of Leukocyte, neutrophil and lymphocyte in 12 patients during peripheral venous blood examination. Among the cases with abnormal counts of blood cell (CBC), 8 showed a reduction in lymphocyte count–more than that of Leukocyte and neutrophil, which indicated that reduced lymphocyte counts might be of great significance in the diagnosis of COVID-19. All the 28 cases in the group underwent chest CT examination, among which 14 were positive, mainly manifesting by ground-glass opacity, with more cases of disease in both lungs than that in single lung. In this group, 8 cases underwent chest X-ray examination before CT examination, but only one of them showed positive manifestations with the finding that positive imaging performances were often prior to the etiological diagnosis.
Therefore, for suspected cases–especially those with no evidence of etiology, it is always impossible to comprehensively and objectively evaluate the lung condition through chest X-ray examination, which may result in misdiagnosis and further affect the treatment and epidemic prevention. In summary, chest CT examination in early stage is relatively reliable and may reduce the rate of missed diagnosis. In this group, 23 cases were confirmed by the first nasopharyngeal sampling of SARS-CoV-2 RNA detection, and the sampling site of the remaining 5 cases who was tested negative for the first time was oropharyngeal, among them, 3 patients were confirmed by the second nasopharyngeal sampling, and 2 patients were confirmed by the third nasopharyngeal sampling. The result of first SARS-CoV-2 RNA detection was false-negative in 5 cases. It was considered be related to the following factors: 1. The amount of viral load in the patient is not enough to be detected during the course of the disease. 2. The collection site of respiratory secretions: it has been reported that the detection rate of SARS-CoV-2 RNA in oropharyngeal sampling is lower than that in nasopharyngeal sampling, which may possibly due to effect of the environment of nasopharynx and oropharynx on SARS-CoV-2 RNA. Meanwhile, the tolerance of the patients results in a longer stay of the swab in the nasopharynx than in the oropharynx. In addition, oropharyngeal sampling is more likely to result in droplet spatter and lead to the occupational exposure. 3. It is related to the technical level, test method, kit, specimen preservation and transportation of the samplers. In summary, for suspected cases, the results of SARS-CoV-2 RNA sampled from a single sample, a single site and a single specimen are not reliable, and nucleic acid testing of multiple times, multiple sites and multiple specimens is required for etiological diagnosis. 4 patients in this group performed diarrhea and SARS-CoV-2 RNA was detected in feces, indicating that the gastrointestinal tract might be a potential route of COVID-19 infection, and this disease was likely to be transmitted through fecal-mouth.However, further studies are needed to determine whether COVID-19 patients without the symptom of diarrhea can be confirmed by fecal samples. Moreover, all cases in this group were treated with α-interferon atomized inhalation and Chinese patent medicine orally before diagnosis, due to the facts that the confirmed patients were not symptomatic and were treated before getting confirmed, antiviral medicine and other treatments were not widely used.