Study characteristics Patient Sampling Purpose: to estimate the prevalence of COVID‐19 in pneumonias during this period and to find the unique features of COVID‐19 as compared to pneumonias caused by other agentsDesign: cross‐sectional, single‐centre, retrospective studyRecruitment: 342 cases of pneumonia were diagnosed in Fever Clinic in Peking University Third Hospital. From these patients, 88 were reviewed by panel discussion as possible or probable cases of COVID‐19, and received 2019‐nCoV detection by RT‐PCRSample size: n = 88 (21 cases)Inclusion criteria: patients visiting the Fever Clinic at Peking University Third Hospital. Based on epidemiological history, epidemiological evidence, fever and/or respiratory symptoms, chest radiological findings and WBC results, cases with possible or probable COVID‐19 were sent for panel discussion and then for 2019‐nCoV detection by RT‐PCRExclusion criteria: COVID‐19 unlikely by panel discussion; lack of CT scan or no signs of pneumonia on CT scan; paediatric patients Patient characteristics and setting Facility cases: 2019‐nCoV real‐time PCR testing, which was positive in 19 cases (confirmed cases). In another 2 patients, though PCR testing was negative, a clinical diagnosis was made according to
epidemiological evidence, consistent clinical and CT findings (clinical cases)Facility controls: for the cases with negative viral detection, the diagnosis of COVID‐19 was excluded based on inconsistent epidemiological, clinical or radiological dataCountry: ChinaDates: 21 January 2020‐15 February 2020SymptomsFever with a mean body temperature of 37.8 C Cough Expectoration Fatigue Headache Dizziness Shortness of breath Myalgia or arthralgia Sore throat Nasal symptoms and diarrhoea Severity of COVID‐19Mild‐moderate: fever and/or respiratory symptoms with pneumonia in radiology examination, without signs of severe or very severe diseases Severe: presence of 1 of the following: respiratory rate ≥ 30 beat/min; SpO2 ≤ 93% at rest; PaO2/FiO2 ≤ 300 mmHg Very severe: presence of 1 of the following: severe respiratory failure requiring mechanical ventilation; shock; complicated with other organ failure and requiring ICU admission Demographics: COVID‐group only: median age was 42.0 years (25th‐75th percentile, 34.5‐66.0 years). Range 24‐85. Male/female: 11 (52.4%)/10 (47.6%)Exposure history: 19/21 (90.5%) had a clear epidemiological history of COVID‐19. 7 patients, from 5 family clusters, had close contact with their family members Index tests Fever with a mean body temperature of 37.8 C Cough Expectoration Fatigue Headache Dizziness Shortness of breath Myalgia or arthralgia Sore throat Nasal symptoms and diarrhoea Target condition and reference standard(s) TC: COVID‐19 pneumonia RS: 2019‐nCoV real‐time PCR testing or clinical diagnosis was made according to epidemiological evidence, consistent clinical and CT findings Flow and timing Time interval not specified Comparative   Notes   Methodological quality Item Authors' judgement Risk of bias Applicability concerns DOMAIN 1: Patient Selection Was a consecutive or random sample of patients enrolled? Unclear     Was a case‐control design avoided? Yes     Did the study avoid inappropriate exclusions? No     Did the study avoid inappropriate inclusions? No     Could the selection of patients have introduced bias?   High risk   Are there concerns that the included patients and setting do not match the review question?     High DOMAIN 2: Index Test (All tests) Were the index test results interpreted without knowledge of the results of the reference standard? Yes     If a threshold was used, was it pre‐specified? No     Could the conduct or interpretation of the index test have introduced bias?   High risk   Are there concerns that the index test, its conduct, or interpretation differ from the review question?     Low concern DOMAIN 3: Reference Standard Is the reference standards likely to correctly classify the target condition? Yes     Were the reference standard results interpreted without knowledge of the results of the index tests? No     Could the reference standard, its conduct, or its interpretation have introduced bias?   Low risk   Are there concerns that the target condition as defined by the reference standard does not match the question?     Low concern DOMAIN 4: Flow and Timing Was there an appropriate interval between index test and reference standard? Unclear     Did all patients receive the same reference standard? Yes     Were all patients included in the analysis? Yes     Could the patient flow have introduced bias?   High risk