Martin‐Sanz 2020.

Study characteristics
Patient Sampling	Purpose: diagnosis of SARS‐CoV‐2 infection (mild COVID‐19 disease); to evaluate the incidence of certain symptoms in a population of HCWs (exposed to COVID‐19‐positive patients) Design: cross‐sectional cohort study, prospective data collection Recruitment: HCW of the University Hospital of Getafe (Madrid, Spain) with suspicion of COVID‐19 infection Sample size: n = 355 (215 cases) Inclusion criteria: HCW with suspicion of COVID‐19 infection. Suspicion of COVID‐19 was determined by the presence of either cough, fever (> 37.5 °C), headache, or breathlessness, regardless of contact with a COVID‐19 patient Exclusion criteria: inconclusive PCR results
Patient characteristics and setting	Facility cases: positive RT‐PCR for SARS‐CoV‐2 Facility controls: negative RT‐PCR for SARS‐CoV‐2 Country: Spain Dates: 15 March 2020‐07 April 2020 Symptoms and severity: mild to moderate severity (only 14 patients (3.94%) developed pneumonia or severe symptoms that required hospitalisation) Demographics: age: overall mean 42.9 years (SD = 0.67) M%/F%: cases 20.5/79.5, controls 17.1/82.9 Exposure history: not specified
Index tests	Cough + hyposmia Hyposmia Dysthermia + hyposmia Hypogeusia Dysthermia Cough Myalgia Asthenia Rhinorrhea Back pain Chest pain Dyspnoea Diarrhoea Headache Sore throat
Target condition and reference standard(s)	TC: SARS‐CoV‐2 infection RS: SARS‐CoV‐2 next‐generation sequencing or real‐time PCR methods (nasal and pharyngeal swabs)
Flow and timing	Not specified
Comparative
Notes	Article states that it is a case‐control study, while it is not (all consecutive suspected HCW's enrolled and tested) 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?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Yes
Did the study avoid inappropriate inclusions?	Yes
Could the selection of patients have introduced bias?		Low risk
Are there concerns that the included patients and setting do not match the review question?			Low concern
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?	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?	Unclear
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Unclear risk