Study characteristics
Patient Sampling  Purpose: to evaluate association of patient‐reported symptoms with a focus on sense of smell and taste and SARS‐CoV‐2 infectionDesign: internet survey of patients after presentation to a single‐centreRecruitment: email invitation with 1 phone call follow‐up to everyone who was tested for COVID‐19 between 3 March 2020 and 29 March 2020Sample size: n = 262 (cases: 59)Inclusion criteria:adult patients who presented to the institution and got tested for COVID‐19
analysis on responders to email survey (responses: cases 59/102, controls 203/1378)
Exclusion criteria:
Patient characteristics and setting  Facility cases: SARS‐CoV‐2‐positiveFacility controls: SARS‐CoV‐2‐negativeCountry: USA, San DiegoDates: 3 March 2020‐29 March 2020Symptoms and severity:larger representation of ambulatory patients (higher response rate to survey)
severity ‐ hospital admission: cases 4/59, controls 14/203
Demographics: adults only, M/F: cases 29/29, controls 69/132Exposure history: not specified
Index tests  Fatigue
Loss of taste
Fever
Loss of sense of smell
Cough
Headache
Myalgia
Dyspnoea
Diarrhoea
Nasal obstruction
Sore throat
Rhinorrhoea
Nausea
Target condition and reference standard(s)  TC: SARS‐CoV‐2 infection
RS: PCR for SARS‐CoV‐2 (sample not specified)
Flow and timing  PCR taken at presentation, not specified when the questionnaire was sent. Patients had to list their symptoms at presentation.
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?  Yes      
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?  No      
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?  Unclear      
Were the reference standard results interpreted without knowledge of the results of the index tests?  Yes      
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?     Unclear risk