The COVID-19 pathogen is an enveloped novel coronavirus of the β genus with polymorphic morphology and 60–140 nm diameter. It is highly homologous with the SARS virus and has been named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by the International Committee on Taxonomy of Viruses. COVID-19 is a disease characterized primarily by lung inflammation and can also cause injury and corresponding symptoms in the intestines, liver and nervous system. Its primary pathological characteristic is bilateral diffuse alveolar injury.
In the 931 cases retrospectively analyzed in this study, the age range was 14–75 years, the patients were, predominantly, 30–60 years old and the incidence rate was similar between males and females, which is consistent with data released by the Chinese Center for Disease Control and Prevention. Symptoms in patients with mild cases of COVID-19 mainly include fever, cough (dry cough), myalgia and fatigue (the four main symptoms of COVID-19) with a few upper respiratory tract symptoms, such as nasal congestion and runny nose, suggesting that the virus mainly attacks lung tissue. Studies have shown that the target of SARS-CoV-2 is ACE2, which is widely expressed in lung tissue. Chest distress and dyspnea are also rare and are mainly associated with the type of disease, but 19 patients in the present study were transferred to other hospitals due to chest distress and dyspnea. This is an important reason for transfer, so this patient population must be closely monitored in clinical practice. A small number of patients also presented with diarrhea. Notably, the proportion of asymptomatic patients was 10%. Attention should be given to investigating the epidemiological history of patients. Currently, known sources of infection are primarily other people infected with the novel coronavirus (including those in the incubation period or who are asymptomatic) [ 5], so screening and timely treatment of such patients is an essential link in epidemic prevention and control. The most common chest CT manifestations in COVID-19 patients are bilateral multiple subpleural ground-glass opacities, fine reticular opacities, patchy opacities and vascular thickening[10,11]. The mild disease COVID-19 summarized in this study is consistent with this kind of imaging change, suggesting that chest CT is a screening method worthy of promotion in the population with epidemiological history, so as to reduce the missed diagnosis of asymptomatic or mild symptom patients with COVID-19. Of course, there were patients with mild cases of COVID-19 that suffered from anxiety and insomnia (12.13%). The psychiatrists in our group conducted timely psychological intervention and guidance and our nursing group led a Baduanjin qigong group, and rolling television broadcasts that announced that COVID-19 was preventable and treatable and other interventions have also achieved good results.
In order to properly achieve early diagnosis and treatment of COVID-19 patients and implement collection and treatment of cases in Wuhan, Hubei Province, clinical diagnosis cases were added to the Hubei Province diagnostic criteria in the "Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (draft 5th edition)". Namely, suspected cases with the imaging presentation of pneumonia were confirmed as clinically diagnosed cases. In the present study, the proportion of cases testing negative for novel coronavirus nucleic acid was 44.55%, indicating that a very high percentage of clinically diagnosed cases were diagnosed with COVID-19. On February 12, 2020, the total number of clinically diagnosed cases in the Hubei Province increased by 13332. Most of these cases were predominantly mild and were situated in Wuhan City, which greatly increased the pressure on the Wuhan medical system. In order to address this problem, the Central Steering Committee urgently mobilized 20 national medical assistance groups and medical groups from various provinces and cities, and built shelter hospitals in a short period to treat patients in a timely manner and maximize isolation and treatment of patients with mild cases.
A mobile field hospital usually uses a medical shelter as a carrier and has different medical or technical support functions. It is designed to respond to sudden disasters, such as natural disasters, shipwrecks, plane crashes, wars, terrorist incidents, public health emergencies and so on. The shelter hospitals used in Wuhan for COVID-19 prevention relied on repurposed factory buildings, gymnasiums, exhibition centers, large shopping malls and other buildings with open indoor spaces as ward units. Mobile shelter hospitals are used as medical functional units and technical support units to form a modular field health facility. They are characterized by construction and transformation of a temporary treatment site at a minimal cost and in a short time in order to effectively control the source of infection and maximize patient care. Shelter hospitals in China have been utilized in emergency medical rescue operations such as the 2008 Sichuan earthquake and the 2010 Yushu earthquake in Qinghai, but this was the first time they have been used to respond to public health incidents involving infectious diseases, and there have been no other mature experiences from which to draw lessons. Therefore, in order to standardize diagnosis and treatment at shelter hospitals, the Medical Administration and Management Bureau of the National Health Commission established three shelter hospitals that were put into use at early stages and compiled a "Shelter Hospital Operational Manual", which provided an important reference for the management of subsequently established shelter hospitals. The "Shelter Hospital Operational Manual" describes in detail what a shelter hospital is, background information about its construction and general condition of shelter hospitals in Wuhan. It also lays out the criteria for patient admission, check-in and processing, pre-examination and triage, treatment protocols, transfer and processing of severely ill patients, and discharge criteria. In addition, a shelter hospital management system based on the principles of directional admission, centralized isolation, unitized partition management, standardized treatment and bidirectional transfer was established. Shelter hospital operating conditions were strictly implemented and the Zhuankou shelter hospital achieved "zero patient deaths and zero medical personnel infections". The extremely low transfer rate due to exacerbation of primary disease (6.98%) also confirms the feasibility of shelter hospitals for mild cases of COVID-19 during prevention and treatment of a sudden infectious disease. However, among the transferred patients, the number of those with underlying diseases was significantly higher than of those without- the difference was statistically significant. This indicates that some patients observed in the shelter hospital were still in an exacerbated state and most have underlying diseases. Therefore, during isolation and observation, special attention should be given to patients with underlying diseases.