Yombi 2020.

Study characteristics
Patient Sampling	Purpose: diagnosis of SARS‐CoV‐2 infection (mild COVID‐19 disease); diagnosis of SARS‐CoV‐2 infection, using clinical signs in HCWs Design: cross‐sectional cohort study, retrospective data collection Recruitment: period 1: (before 30 March 2020) HCWs were tested only if they had fever and respiratory symptoms (some physicians were tested without fever); period 2 (after 30 March 2020), HCWs were tested if they had respiratory symptoms with or without fever Sample size: n = 536 (175 cases) Inclusion criteria: not specified (all suspected HCWs) Exclusion criteria: not specified
Patient characteristics and setting	Facility cases: all suspected HCWs with a positive RT‐PCR Facility controls: all suspected HCWs with a negative RT‐PCR Country: Belgium Dates: 16 March 2020‐24 April 2020 Symptoms and severity: not specified (from tables: mild to moderate severity) Demographics: % age < 45 years: cases: 56.6%, controls: 62.3% gender: % female cases: 67.4%, controls: 73.1% Exposure history: not specified (all HCWs)
Index tests	Fever Cough Shortness of breath Sore throat Fever + cough Fever + cough + shortness of breath Fever + cough + sore throat
Target condition and reference standard(s)	TC: SARS‐CoV‐2 infection RS: PCR for SARS‐CoV‐2 (sample not specified)
Flow and timing	Not specified
Comparative
Notes	Funding: none declared
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?	Unclear
Did the study avoid inappropriate inclusions?	Unclear
Could the selection of patients have introduced bias?		Unclear risk
Are there concerns that the included patients and setting do not match the review question?			Unclear
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?	Unclear
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?	Unclear
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?	Unclear
Could the patient flow have introduced bias?		Unclear risk