Abstract
Novel coronavirus disease 2019 (COVID-19) was present in most provinces of China after January 2020. We implemented a surveillance and screening strategy that included early detection of laboratory-confirmed COVID-19 cases and people who were exposed to the disease in Guangming District of Shenzhen. Separate targeted treatment and management strategies were applied to confirmed and suspected cases. From January 23 to March 13, 2020, we found 12 suspected cases, and 11 were confirmed as positive. Although eight of the 11 confirmed cases were family-aggregated, they were all imported cases with common exposure, which did not further cause local community transmission, and no medical staff were infected. After February 14, when the last case was confirmed, there were no newly confirmed cases for 28 consecutive days under the strict outbreak control. The targeted and whole-society involved prevention and control measures prevented the spread of the disease in a very short time and provided a strong guarantee for the orderly recovery of returning to work and social activities.
Keywords
Background
In late December 2019, a cluster of patients, epidemiologically linked to a seafood market in Wuhan, were admitted to hospital with an initial diagnosis of pneumonia of an unknown etiology (Chan et al., 2020; Huang et al., 2020; Zhu et al., 2020). These patients were tested and confirmed to have viral infectious pneumonia, called the novel coronavirus disease 2019 (COVID-19) (Chen et al., 2020; Wu et al., 2020). Unfortunately, no targeted therapy existed for COVID-19 and no results of randomized controlled trials were available (Dhama et al., 2020; Liu et al., 2020; Pang et al., 2020; Yuen et al., 2020). The COVID-19 pandemic spread widely and rapidly in China and other countries. From the public health standpoint, disease control that takes into account the impact of governmental intervention, diversity of human-to-human transmission and migration may curb the outbreak effectively. However, whether current containment measures could effectively curb the disease spread was unknown.
Guangming District with 156 square kilometers area and 1.38 million populations is located in the northwest of Shenzhen. On January 23, 2020, the first case of COVID-19 infection confirmed in the hospital of Guangming District led to the prevention, control and management of this imported epidemic. The purpose of this paper was to describe the strategies for the control and prevention of the COVID-19 epidemic in Shenzhen Guangming District and the results of the first 50 days, from January 20, as of March 13.
Method
Establishment of an Epidemic Prevention and Control System Led by the Government and Involving the Whole Society
Guangming District of Shenzhen formulated the inter-agency mechanism that integrated early identification, early diagnosis, early isolation, and early protection for the COVID-19 epidemic. A district-wide epidemic prevention and control system was established under the major leadership of the district government.
Screening for COVID-19 Cases and Blocking the Routes of Transmission
From January 20, two designated hospitals set up fever clinics and negative pressure observation rooms to screen suspected cases who had symptoms (fever, dry cough, fatigue, sputum production, headache, etc.) and a history of traveling in an outbreak area or having close contact with a confirmed case in the past 14 days. The Shenzhen Guangming District Center for Disease Control and Prevention (CDC) conducted laboratory tests for suspected cases. Patients with positive infection were sent by negative-pressure ambulance to the Third People’s Hospital of Shenzhen for inpatient treatment, and corresponding samples for confirmatory testing were sent to the Shenzhen and Guangdong CDC. Furthermore, Guangming District CDC conducted a case investigation to identify close contacts. Those with no symptoms were sent by negative-pressure ambulance to the centralized medical observation site for 14-day medical observation; COVID-19 screening laboratory tests were conducted on Days 1 and 14. Twice negative persons were released and informed to stay at home as much as possible, whereas COVID-19 positive patients were treated following the above procedures. In addition, the confirmed case with completed treatment should carry out a 14-day medical observation following the same process as for close contacts.
Community screening for outbreak contacts was launched on January 24, as body-temperature assessment became mandatory for entry to communities and various public facilities. People with a history of outbreak contact completed the electronic information registration and were isolated at home for a 14-day medical observation. Community health service staff, community police and community workstation staff visited every house to elicit contact histories, symptoms and body temperature assessments. The symptomatic persons were sent to designated hospitals by negative-pressure ambulance.
Detection stations were set up at the major traffic stations and intersections of the district to conduct temperature assessments and daily investigation by medical staff. The measures adopted for local people with a history of disease contact were the same as for the community screening procedures, when people without a fixed residence in the district were sent to the designated central observation site for medical observation.
Protecting the Susceptible Population
Via social media, government, community neighborhood committees publicized, informed, and persuaded residents to stay at home as much as possible. Crowd-gathering events were suspended; residents were recommended to shop or go to school online to avoid the flow of people, gathering, and direct contact. The district expert group formulated the preventive disinfection guidelines for different types of living places. Information to improve residents’ health literacy, prevention and control consciousness, and self-prevention ability was rapidly disseminated by traditional paper media, TV, radio, Internet, mobile phone and other channels. Everyone was instructed to wear surgical mask, when they needed to go out. The frontline staff were equipped with different protective equipment to ensure the protection needs. In addition, 100 observation beds were provided in the observation room of the hospital; and separate access was provided for medical staff and patients.
Protection in Resumption of Work and Production
We promoted the resumption of work and production in a scientific and orderly manner. Firstly, the companies and organizations assumed primary responsibility for establishing working systems and preparing materials for epidemic prevention and control. Secondly, the companies and organizations were responsible for publicity for staff returning to work and for persuading staff from outbreak areas to delay returning to work. Thirdly, related medical guidance and health management teams were formed to guide and urge the health administrators of each enterprise to carry out health, meal and safety management as well as environmental disinfection and to collect and evaluate the materials reported by the health administrators to prevent and control the epidemic as soon as possible.
Data Analysis
Statistical description methods such as ratio, mean (±SD) were used to analyze the survey and work data. The relationship map described the relationship between confirmed cases and close contacts.
Results
Clinic for Screening for Fever at Designated Hospitals
A total of 6,952 cases were diagnosed and treated in the fever clinic of two designated hospitals from January 23 to March 13, 2020 (Figure 1A); 1,085 cases required a laboratory test and observation. Six suspected cases with positive laboratory test screen for the first time were sent to inpatient treatment (Figure 1B); five of these cases were confirmed.
Number of people screened for COVID-19 in Guangming District of Shenzhen according to different stages.
Screening for Outbreak Contacts
From January 23 to March 13, 2020, 15,125 people completed a 14-day medical observation at home and 423 were still in a medical observation period on March 13 (Figure 1C). Overall, 149 cases had fever and respiratory symptoms and four cases were positive for COVID-19 on laboratory testing in designated hospitals (Figure 1D). One resident, who concealed his exposure history, was not screened in the fever clinic; after receiving feedback from Wuhan, he was later confirmed as a worker of the south China seafood market and detected positive by the district and municipal CDC.
Among 659,336 persons receiving temperature assessments in the detection stations (Figure 1E); 28 people had abnormal body temperature and 4,891 came from the outbreak areas from January 26 to March 13. None were COVID-19 confirmed cases by diagnoses in designated hospitals and medical observation in the community (Figure 1F).
A total of 90 people were reported to have close contacts with the seven suspected cases confirmed by the positive initial screening; 33 individuals were in Shenzhen. Five positive cases were identified and confirmed; two cases had no clinical symptoms.
Epidemiological Characteristics of Confirmed Cases
Among the 11 confirmed cases, seven were women. The mean (±SD) age was 36.80 (±22.6) years, with the youngest 5 years old and the oldest 62 years old. The main occupations were migrant workers (seven cases, 63.64%) and students (three cases, 27.27%), with no medical staff infected. Furthermore, 10 (90.91%) were people who had returned to Guangming District from Hubei province within 14 days before treatment: nine (81.82%) drove or entered by private car and 1 (9.09%) entered by bullet train and then by public transport. Two (18.18%) cases showed disease before returning to Shenzhen, six (54.55%) showed disease after returning to Shenzhen, and two (18.18%) were asymptomatic. The other case (9.09%) was a localized with unknown exposure, possibly caused by an infected relative on holiday.
The time from onset of the first confirmed case to confirmation of the last case on February 14 was 23 days. Nine of 11 confirmed cases had mild symptoms such as fever, cough, rhinitis and fatigue before diagnosis. The median time from onset to hospitalization was two days (range 0–9 days) (Figure 2). Only six individuals went to the hospital for treatment after symptom onset: the median time from onset to first visit was 1 day (range 0–3 days); the median time from the first visit to hospital to hospitalization was 4.5 days (range 1–9). Eight of confirmed cases were from four families with a common exposure history. There was only one close contact in Hubei province that showed disease 14 days after the onset of confirmed cases by following up more than 30 days. None of the remaining close contacts showed disease, and none of them in Shenzhen were second-generation cases.
Time from symptom onset to hospitalization for confirmed cases.
In total, 12,435 companies and organizations returned to work in Guangming District, with a resumption rate of 95.57%, and 376,449 workers returned to work, with a return rate of 88.4%. No confirmed case was found in resumption of work and production.
Discussion
COVID-19, as a new infectious disease, was first discovered to transmit among people in late 2019 (Wu et al., 2020; Zhu et al., 2020). Limited information on COVID-19 was available and no vaccine or specific treatment plan had been developed (Adhikari et al., 2020; Corman et al., 2020; Dhama et al., 2020; Liu et al., 2020; Pang et al., 2020; Yuen et al., 2020). Subsequent studies found that human-to-human transmission occurred primarily via direct contact or through droplets from an infected people (Li et al., 2020; Riou & Althaus, 2020; Xu et al., 2020), and the virus was highly contagious. Although there is no specific treatment and control, the appropriate public health measures can effectively control the COVID-19 epidemic under the participation of the whole society based on the prevention and control strategy of respiratory infectious diseases.
On January 23, after identifying the first case in a fever clinic of the designated hospital, the Guangming District of Shenzhen quickly started pathogen screening. Laboratory test screening was performed for people with a history of exposure and related clinical symptoms. Those found positive were sent to hospital quickly. Home or concentrated medical observation was carried out for laboratory test–negative people to prevent direct contact with non-infected people as quickly as possible and to reduce the spread of the disease. In addition, considering that the specific distribution of pathogens was not known, the district government led a program to verify cases in outbreak areas and a screening program of people with a history of epidemic exposure. It successively carried out laboratory test screening to identify potential infected persons to protect and isolate high-risk populations. At the same time, the government conducted risk communication, emergency education, and behavior guidance for the general public to urge residents to stay home as much as possible, perform ventilation and disinfection, wash their hands frequently, and wear masks. Other measures such as suspension of non-essential public activities and strict site disinfection were carried out for necessary-business premises, with temperature assessed for staff and entering groups, inquiries about epidemic exposure history, and encouragement to maintain distance, etc. also conducted by the government. These measures decreased the density of people in public places, minimized the flow of people and reduced the probability of virus transmission to the greatest extent.
With the combined measures, the Guangming District took only 13 days (January 24 to February 5) to complete the investigation, diagnosis and treatment of imported cases. As of March 13, no local community transmission had occurred. Although four family aggregation cases occurred among 11 confirmed cases, they were all co-exposed people living in outbreak areas. Moreover, the 11 imported cases caused no second-generation transmission cases in Guangming District and no infections occurred in medical staff. Thus, the prevention and control measures formulated and implemented by the Guangming District were efficient and highly targeted and timely blocked the spread of the epidemic. In addition, to guarantee the prevention and control of the epidemic, the Guangming District implemented the policy of giving priority to resuming work and production. Under the strict implementation of epidemic prevention and control measures, there were no confirmed cases due to the influx of a large number of people from other cities to resume work and production. It took 50 days from the occurrence of the epidemic to the general recovery of social and production activities. Efficient and comprehensive prevention and control measures guaranteed the quick resumption of work and production.
Conclusion
From the epidemic prevention and control measures implemented in Guangming District, we summarize the three main effective containment measures as follows: 1) identify pathogens or cases to isolate them as much as possible to control the source of infection; 2) restrict the movement of people and prevent close physical contact between people to block the routes of transmission; and 3) strengthen the ventilation and disinfection of residents’ living and working environment, wash hands frequently, stay home as much as possible, wear masks when going out, and maintain a distance of more than 1 m between people to protect susceptible populations. The inter-agency mechanism that integrated early protection, identification, diagnosis, and isolation effectively curbed the rapidly growing outbreak. We hope that our experience can help inform medical staff and other countries.
Footnotes
Authors’ Note
All data generated or analyzed during this study are included in this published article. This study did not refer to use of clinic species and animal experiments.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
