Prevention of SARS-CoV-2 transmission from international arrivals: Xiaotangshan Designated Hospital, China

Abstract A surge in the number of international arrivals awaiting coronavirus disease 2019 (COVID-19) screening overwhelmed health-care workers and depleted medical resources in designated hospitals in Beijing, China in March 2020. The People’s Government of Beijing Municipality therefore issued a policy which required the mandatory transfer of all asymptomatic passengers arriving from a foreign country to designated quarantine hotels, and the transfer of passengers with fever or respiratory symptoms to designated hospitals. Xiaotangshan Designated Hospital, a severe acute respiratory syndrome hospital in 2003, was rapidly renovated and put into operation with the main tasks of screening and isolating symptomatic international arrivals at Beijing Capital International Airport, providing basic medical care for mild to moderate COVID-19-positive cases, and rapidly referring severe to critical COVID-19-positive cases to higher-level hospitals. During the month-long period of its operation, 2171 passengers were screened and 53 were confirmed as having COVID-19 (six severe to critical). We describe how the use of Xiaotangshan Designated Hospital in this way enabled the efficient grouping and assessment of passengers arriving from a foreign country, the provision of optimal patient care without compromising public safety and the prioritization of critically ill patients requiring life-saving treatment. The designated hospital is a successful example of the World Health Organization’s recommendation to renovate existing medical infrastructures to improve the COVID-19 response capacity. The flexible design of Xiaotangshan Designated Hospital means that it can be repurposed and reopened at any time to respond to the changing pandemic conditions.


Introduction
The World Health Organization (WHO) declared the coronavirus disease (COVID-19) outbreak as a public health emergency of international concern on 30 January 2020. 1 At that date, 7818 cases had been confirmed globally. 2 In Beijing, local transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was contained by the end of February 2020, after 428 cases had been reported (Fig. 1). However, a combination of the alarming level of transmission in foreign countries and the fact that Beijing is a major hub of international aviation meant that the city faced the potential reintroduction of the virus. 3 Screening and isolating cases arriving from a foreign country therefore became the top priority.
During March 2020, around 100 000 passengers (4000 with symptoms) arrived at Beijing Capital International Airport and required quarantine or screening, placing a huge burden on established COVID-19 designated hospitals. All screening was initially performed at Beijing Ditan Hospital, a traditional infectious disease hospital and a higher-level hospital for treating severely ill COVID-19 patients. 4 However, the surge in the number of arrivals requiring to be screened led to the diversion of medical resources originally allocated for the treatment of existing patients with severe COVID-19; health-care workers became overwhelmed and the supplies of medical equipment, such as nucleic acid detection tests and computed tomography scanning, were rapidly depleted. 4 Beijing was in urgent need of a new dedicated facility to increase its capacity to screen and isolate travellers arriving from a foreign country, and to optimize the allocation of medical resources. Xiaotangshan Hospital, located on the outskirts of Beijing adjacent to Beijing Capital International Airport and Beijing Ditan Hospital, was a severe acute respiratory syndrome (SARS) designated hospital in 2003. 5 The first hospital rapidly built in China to tackle an outbreak of a single infectious disease, it represented a major contribution to China's response to the public health emergency. After the outbreak of COVID-19, the original Xiaotangshan Hospital model was replicated in Wuhan when the city rapidly built a number of designated hospitals (such as Huoshenshan and Leishenshan) to ease the shortage of beds for COVID-19 patients. 6,7 As part of the planning for a possible surge in COVID-19 cases, Xiaotangshan Hospital was expanded, renovated and repurposed, and renamed Xiaotangshan Designated Hospital by the People's Government of Beijing Municipality in January 2020. [8][9][10][11] The designated hospital was formally put into operation on 16 March 2020 to screen and isolate arrivals at Beijing Capital International Airport with fever or respiratory symptoms; provide basic medical care for mild to moderate confirmed COVID-19 cases; and rapidly refer severe to critical confirmed COVID-19 cases to higher-level hospitals.
On 11 March 2020, the People's Government of Beijing Municipality issued a policy which required the mandatory transfer of all asymptomatic travellers arriving from a foreign country to designated quarantine hotels, and the transfer of passengers with fever or respiratory symptoms to designated hospitals. Although an important alternative to hospital isolation, 12 voluntary self-isolation of travellers is unlikely to be Xiaotangshan Designated Hospital, China Zujin Luo et al.
fully effective because of a general lack of adherence to the required living conditions; family members are put at risk and self-isolators can experience psychological stress. 12,13 Further justification for quarantining at designated sites is that unnecessary delays are avoided for any required medical care or even rapid referral to a hospital. 13 Xiaotangshan Designated Hospital, together with Beijing Ditan Hospital, designated quarantine hotels and dedicated transfer vehicles, comprised the primary medical system in the prevention of virus transmission from international arrivals at Beijing Capital International Airport. We describe the structure and design of Xiaotangshan Designated Hospital, and the resources available to it. We also explain the function and operation of the designated hospital, and discuss its effectiveness and value in responding to the pandemic and preventing the transmission of the virus from overseas travellers.

Structure and resources
Xiaotangshan Designated Hospital consisted of two separate medical areas: a screening area with 750 single-bed wards, and a treatment area with nearly 150 beds. Both areas included three separate contamination-level zones: a contaminated zone where patients resided; a semi-contaminated zone where health-care workers removed personal protective equipment; and a clean zone where health-care workers received supplies, performed clerical work and rested (Fig. 2). Both areas also included two separate corridors linking the infectious disease isolation wards: [13][14][15][16] one corridor for use by isolating travellers and another for health-care workers (Fig. 2).
Xiaotangshan Designated Hospital was well equipped with oxygen therapy devices, mechanical ventilators, and nucleic acid detection and computed tomography scanning equipment. To ensure efficient operation of the hospital and to maximize its screening capacity for COVID-19, it was crucial to have sufficient human resources. Beijing authorities mobilized health-care workers from 22 hospitals across the city to support Xiaotangshan Designated Hospital. 17 Health-care workers responded positively regardless of their circumstances; 18 many even volunteered their services for the designated hospital, despite the known risk of infection. All health-care workers received rigorous pre-employment professional training that included: identifying the symptoms of COVID-19; understanding the guidelines regarding COVID-19 diagnosis and treatment; practising the standard process for wearing and removing personal protective equipment; and being aware of the correct corridors to use to access the isolation wards.
The People's Government of Beijing Municipality convened a leadership group for COVID-19 in Xiaotangshan Designated Hospital. This group, led by the deputy director of the Beijing Municipal Health Commission, was created to manage the hospital's daily operations. The local government coordinated with various departments to ensure that food and medical supplies were available for both health-care workers and isolating travellers, and that basic facilities such as water, electricity and security were available. 17 To ensure that the public understood and supported the mission of Xiaotangshan Designated Hospital, the hospital management team held several press conferences and arranged multiple interviews with officials and health-care workers to provide information about the hospital.

Function and operation Screening
Travellers arriving at Beijing Capital International Airport with fever or respiratory symptoms were transferred to Xiaotangshan Designated Hospital, and tested for SARS-CoV-2 nucleic acid in combined nasopharyngeal and oropharyngeal swabs and serum antibodies; passengers also received chest computed tomography scans and routine blood tests. COVID-19 was confirmed if passengers tested positive for SARS-CoV-2 nucleic acid or their serum immunoglobulin M and immunoglobulin G were both positive. 19 Dur-  ing screening, which took an average of 30 hours (from 11 hours minimum to over 5 days), all passengers were strictly subjected to single-room quarantine to avoid nosocomial infection of passengers whose symptoms were unrelated to SARS-CoV-2. As well as food and accommodation, within the screening area passengers could also access basic medical care, a disease consultant and emotional support. COVID-19 was ruled out if both the nucleic acid test and any serum antibodies were negative, as well as no obvious abnormalities on the chest scan and in the blood test. 19 COVID-19-negative passengers were transferred to designated quarantine hotels by dedicated transfer vehicles for a 14-day observation period. If passengers were asymptomatic and had a negative nucleic acid test on day 14, they could return to their homes by dedicated transfer vehicle. To prevent the transmission of COVID-19 with a possible incubation period of more than 14 days, self-isolation was recommended for an additional 14 days. 20 Anyone who developed a fever or respiratory symptoms during hotel quarantine was returned to the screening area of Xiaotangshan Designated Hospital for COVID-19 testing.

Mild and moderate cases
If mild (with symptoms including cough, sore throat, fatigue, myalgia or headache, and no signs of pneumonia on chest scan) or moderate (with symptoms also including fever and dyspnoea and pneumonia evident from the chest scan) COVID-19 was diagnosed, patients were transferred from the screening area to the treatment area of the designated hospital via a dedicated in-hospital passage for isolation and treatment. 19 Patients received basic medical care (including antiviral, antibiotic, antipyretic and traditional Chinese medicine) as well as intravenous fluids, conventional and high-flow oxygen supplementation and respiratory rehabilitation. Health-care workers measured the body temperature, heart rate, blood pressure, respiratory rate and oxygen saturation of patients more than four times per day to monitor the progression of the disease. Basic life support (including cardiopulmonary resuscitation, rapid defibrillation, endotracheal intubation and subsequent invasive ventilation) and close electrocardiographic monitoring were provided in two temporary singlebed intensive care units for rapidly deteriorating patients. In addition to basic food and accommodation, patients could also access the Internet as well as any required emotional support. For professional guidance, the clinical conditions of all patients were reported to a higher-level specialist group in Beijing during an online consultation every day.

Discharge conditions
Patients in the treatment area were discharged if they met all of the following criteria: 19 (i) no fever for > 3 days; (ii) significant improvement in respiratory symptoms; (iii) obvious absorption of inflammation on chest scan; and (iv) two consecutive negative nucleic acid tests for SARS-CoV-2 with a sampling interval of more than 24 hours. Discharged patients were then transferred to a designated quarantine hotel for a 14-day period of medical observation. Self-isolation was then recommended for an additional 14 days after leaving the quarantine hotel.

Severe and critical cases
Whether during examination in the screening area or the treatment area, patients were quickly referred to a higherlevel designated hospital, by dedicated transfer vehicle via a pre-established referral pathway, for intensive care if they met any of the following criteria: 19 (i) a respiratory rate of ≥ 30/min; (ii) an oxygen saturation as measured by pulse oximetry of ≤ 93%; (iii) an arterial oxygen tension of inspired oxygen of ≤ 300 mmHg; (iv) the expansion of a pulmonary lesion in the chest scan by > 50% within 24-48 hours; or (v) the exacerbation of chronic obstructive pulmonary disease, hypertension, diabetes, coronary heart disease or any other comorbidity requiring advanced medical care.

Effectiveness and value
As a result of the diversion of international flights from Beijing to other ports Fig. 2. Floor plan of a subunit  of entry in China to spread the burden of screening arrivals over many designated hospitals, COVID-19 screening at Xiaotangshan Designated Hospital was gradually reduced and finally suspended on 15 April 2020. 21 Xiaotangshan Designated Hospital admitted a total of 2171 passengers for screening during its month-long period of operation (408 passengers in a single day at its peak on 21 March 2020). Because an average of 30 hours is needed to confirm or exclude a diagnosis of COVID-19, a maximum of 685 passengers were temporarily hospitalized in the screening area on 21 March 2020; however, the full capacity of 750 single-bed isolation wards was not reached at any point. Of the 2171 symptomatic passengers who were screened, 2118 tested negative and 53 were confirmed to have COVID-19. Of the 53 confirmed cases, six were referred to a higher-level hospital for intensive care; the remaining 47 (88.7%) mild to moderate COVID-19-positive cases were discharged from the designated hospital by 28 April 2020. 22, 23 In total, 872 health-care workers staffed the designated hospital, including 102 physicians (specialists in respiratory medicine, infectious disease, critical care medicine, paediatrics or traditional Chinese medicine), 728 nurses and 42 technicians. No healthcare workers became infected with COVID-19.
Xiaotangshan Designated Hospital enabled the efficient grouping and assessing of passengers arriving from a foreign country, as well as the provision of optimal care for all patients without compromising public safety. The des-ignated hospital provided appropriate medical care and isolation for mild to moderate cases, avoiding the risk of transmission associated with a lack of adherence to self-isolation. 12,24 Further, by screening travellers arriving from a foreign country for COVID-19 and treating patients with mild to moderate SARS-CoV-2 infection (which accounted for almost 90% of all COVID-19-positive arrivals), 7 the burden on higher-level designated hospitals was reduced, ensuring that critically ill patients who required life-saving treatment could be prioritized. 4 In other words, the Xiaotangshan Designated Hospital enabled the allocation of Beijing's medical resources in terms of its response to COVID-19 to be fully optimized.
During the operation of Xiaotangshan Designated Hospital, only one case (whose incubation period was > 14 days) was missed. This patient transmitted the virus to three family members after returning home. 25 The infrequency of such events highlights the importance of timely screening, isolation and treatment of imported COVID-19 cases.
WHO recommended in March 2020 that new treatment areas or separate hospitals be established to enhance the response to COVID-19, and that more patient care areas in the health system be repurposed for treating COVID-19, especially severe or critical cases. 26 The opening of Xiaotangshan Designated Hospital was consistent with these recommendations. Other countries with international ports could consider this model of COVID-19 screening, triage, isolation and treatment as part of their public health response to imported cases.
Xiaotangshan Designated Hospital accomplished its mission of responding to the threat of the reintroduction of the virus from a foreign country. In the future, the hospital could be used to respond to other public health emergencies, such as clustered food poisoning or natural disasters. Alternatively, the hospital could be used as a rehabilitation hospital or physical examination centre. In the meantime, the pandemic is not yet over and COVID-19 is still spreading globally; however, the flexible design of Xiaotangshan Designated Hospital means that it can be repurposed according to current conditions and reopened at any time. ■

Acknowledgements:
We thank all health-care workers and construction staff for their contribution to the operation of Xiaotangshan Designated Hospital. Zujin Luo and Yi Zhang have contributed equally to this work. Quanyi Wang is a co-corresponding author.