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Meta-Analysis
. 2022 May 20;5(5):CD013665.
doi: 10.1002/14651858.CD013665.pub3.

Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19

Thomas Struyf  1 , Jonathan J Deeks  2   3 , Jacqueline Dinnes  2   3 , Yemisi Takwoingi  2   3 , Clare Davenport  2   3 , Mariska Mg Leeflang  4 , René Spijker  5   6 , Lotty Hooft  6 , Devy Emperador  7 , Julie Domen  8 , Anouk Tans  1 , Stéphanie Janssens  9 , Dakshitha Wickramasinghe  10 , Viktor Lannoy  9 , Sebastiaan R A Horn  8 , Ann Van den Bruel  1 ; Cochrane COVID-19 Diagnostic Test Accuracy Group  3
Affiliations
Meta-Analysis

Signs and symptoms to determine if a patient presenting in primary care or hospital outpatient settings has COVID-19

Thomas Struyf et al. Cochrane Database Syst Rev. .

Abstract

Background: COVID-19 illness is highly variable, ranging from infection with no symptoms through to pneumonia and life-threatening consequences. Symptoms such as fever, cough, or loss of sense of smell (anosmia) or taste (ageusia), can help flag early on if the disease is present. Such information could be used either to rule out COVID-19 disease, or to identify people who need to go for COVID-19 diagnostic tests. This is the second update of this review, which was first published in 2020.

Objectives: To assess the diagnostic accuracy of signs and symptoms to determine if a person presenting in primary care or to hospital outpatient settings, such as the emergency department or dedicated COVID-19 clinics, has COVID-19.

Search methods: We undertook electronic searches up to 10 June 2021 in the University of Bern living search database. In addition, we checked repositories of COVID-19 publications. We used artificial intelligence text analysis to conduct an initial classification of documents. We did not apply any language restrictions.

Selection criteria: Studies were eligible if they included people with clinically suspected COVID-19, or recruited known cases with COVID-19 and also controls without COVID-19 from a single-gate cohort. Studies were eligible when they recruited people presenting to primary care or hospital outpatient settings. Studies that included people who contracted SARS-CoV-2 infection while admitted to hospital were not eligible. The minimum eligible sample size of studies was 10 participants. All signs and symptoms were eligible for this review, including individual signs and symptoms or combinations. We accepted a range of reference standards.

Data collection and analysis: Pairs of review authors independently selected all studies, at both title and abstract, and full-text stage. They resolved any disagreements by discussion with a third review author. Two review authors independently extracted data and assessed risk of bias using the QUADAS-2 checklist, and resolved disagreements by discussion with a third review author. Analyses were restricted to prospective studies only. We presented sensitivity and specificity in paired forest plots, in receiver operating characteristic (ROC) space and in dumbbell plots. We estimated summary parameters using a bivariate random-effects meta-analysis whenever five or more primary prospective studies were available, and whenever heterogeneity across studies was deemed acceptable.

Main results: We identified 90 studies; for this update we focused on the results of 42 prospective studies with 52,608 participants. Prevalence of COVID-19 disease varied from 3.7% to 60.6% with a median of 27.4%. Thirty-five studies were set in emergency departments or outpatient test centres (46,878 participants), three in primary care settings (1230 participants), two in a mixed population of in- and outpatients in a paediatric hospital setting (493 participants), and two overlapping studies in nursing homes (4007 participants). The studies did not clearly distinguish mild COVID-19 disease from COVID-19 pneumonia, so we present the results for both conditions together. Twelve studies had a high risk of bias for selection of participants because they used a high level of preselection to decide whether reverse transcription polymerase chain reaction (RT-PCR) testing was needed, or because they enrolled a non-consecutive sample, or because they excluded individuals while they were part of the study base. We rated 36 of the 42 studies as high risk of bias for the index tests because there was little or no detail on how, by whom and when, the symptoms were measured. For most studies, eligibility for testing was dependent on the local case definition and testing criteria that were in effect at the time of the study, meaning most people who were included in studies had already been referred to health services based on the symptoms that we are evaluating in this review. The applicability of the results of this review iteration improved in comparison with the previous reviews. This version has more studies of people presenting to ambulatory settings, which is where the majority of assessments for COVID-19 take place. Only three studies presented any data on children separately, and only one focused specifically on older adults. We found data on 96 symptoms or combinations of signs and symptoms. Evidence on individual signs as diagnostic tests was rarely reported, so this review reports mainly on the diagnostic value of symptoms. Results were highly variable across studies. Most had very low sensitivity and high specificity. RT-PCR was the most often used reference standard (40/42 studies). Only cough (11 studies) had a summary sensitivity above 50% (62.4%, 95% CI 50.6% to 72.9%)); its specificity was low (45.4%, 95% CI 33.5% to 57.9%)). Presence of fever had a sensitivity of 37.6% (95% CI 23.4% to 54.3%) and a specificity of 75.2% (95% CI 56.3% to 87.8%). The summary positive likelihood ratio of cough was 1.14 (95% CI 1.04 to 1.25) and that of fever 1.52 (95% CI 1.10 to 2.10). Sore throat had a summary positive likelihood ratio of 0.814 (95% CI 0.714 to 0.929), which means that its presence increases the probability of having an infectious disease other than COVID-19. Dyspnoea (12 studies) and fatigue (8 studies) had a sensitivity of 23.3% (95% CI 16.4% to 31.9%) and 40.2% (95% CI 19.4% to 65.1%) respectively. Their specificity was 75.7% (95% CI 65.2% to 83.9%) and 73.6% (95% CI 48.4% to 89.3%). The summary positive likelihood ratio of dyspnoea was 0.96 (95% CI 0.83 to 1.11) and that of fatigue 1.52 (95% CI 1.21 to 1.91), which means that the presence of fatigue slightly increases the probability of having COVID-19. Anosmia alone (7 studies), ageusia alone (5 studies), and anosmia or ageusia (6 studies) had summary sensitivities below 50% but summary specificities over 90%. Anosmia had a summary sensitivity of 26.4% (95% CI 13.8% to 44.6%) and a specificity of 94.2% (95% CI 90.6% to 96.5%). Ageusia had a summary sensitivity of 23.2% (95% CI 10.6% to 43.3%) and a specificity of 92.6% (95% CI 83.1% to 97.0%). Anosmia or ageusia had a summary sensitivity of 39.2% (95% CI 26.5% to 53.6%) and a specificity of 92.1% (95% CI 84.5% to 96.2%). The summary positive likelihood ratios of anosmia alone and anosmia or ageusia were 4.55 (95% CI 3.46 to 5.97) and 4.99 (95% CI 3.22 to 7.75) respectively, which is just below our arbitrary definition of a 'red flag', that is, a positive likelihood ratio of at least 5. The summary positive likelihood ratio of ageusia alone was 3.14 (95% CI 1.79 to 5.51). Twenty-four studies assessed combinations of different signs and symptoms, mostly combining olfactory symptoms. By combining symptoms with other information such as contact or travel history, age, gender, and a local recent case detection rate, some multivariable prediction scores reached a sensitivity as high as 90%.

Authors' conclusions: Most individual symptoms included in this review have poor diagnostic accuracy. Neither absence nor presence of symptoms are accurate enough to rule in or rule out the disease. The presence of anosmia or ageusia may be useful as a red flag for the presence of COVID-19. The presence of cough also supports further testing. There is currently no evidence to support further testing with PCR in any individuals presenting only with upper respiratory symptoms such as sore throat, coryza or rhinorrhoea. Combinations of symptoms with other readily available information such as contact or travel history, or the local recent case detection rate may prove more useful and should be further investigated in an unselected population presenting to primary care or hospital outpatient settings. The diagnostic accuracy of symptoms for COVID-19 is moderate to low and any testing strategy using symptoms as selection mechanism will result in both large numbers of missed cases and large numbers of people requiring testing. Which one of these is minimised, is determined by the goal of COVID-19 testing strategies, that is, controlling the epidemic by isolating every possible case versus identifying those with clinically important disease so that they can be monitored or treated to optimise their prognosis. The former will require a testing strategy that uses very few symptoms as entry criterion for testing, the latter could focus on more specific symptoms such as fever and anosmia.

PubMed Disclaimer

Conflict of interest statement

Thomas Struyf: none known

Jonathan J Deeks: no relevant interests; published eight podcasts, including Talk Evidence (BMJ), More‐or‐Less (Radio 4), Inside Science (Radio 4), The Newscast (Radio 4). Five opinion pieces in Guardian, unHerd and the BMJ. Numerous television, radio and mainstream media interviews giving substantial coverage of scientific issues related to test evaluation for COVID‐19. Presented evidence to the House of Lords Select Committee, and the All Parliamentary Party Investigation on COVID‐19. Two invited editorials on COVID‐19 for the BMJ; Editor, Cochrane Diagnostic Test Accuracy Review editorial team

Jacqueline Dinnes: no relevant interests; Editor, Cochrane Diagnostic Test Accuracy Review editorial team

Yemisi Takwoingi: no relevant interests; Editor, Cochrane Infectious Diseases; Statistical Editor, Cochrane Bone, Joint and Muscle Trauma; Editor, Cochrane Diagnostic Test Accuracy Review editorial team

Clare Davenport: no relevant interests; Contact Editor for Cochrane Diagnostic Test Accuracy Review editorial team and was not involved in the editorial process for this review

Mariska MG Leeflang: no relevant interests; team member, Cochrane Diagnostic Test Accuracy Review editorial team

René Spijker: none known

Lotty Hooft: no relevant interests; editorial roles with the Cochrane Diagnostic Test Accuracy Review editorial team and Prognosis Methods Group implementation team

Devy Emperador: no relevant interests; employed by FIND with funding from DFID and KFW. FIND is a global non‐for profit product development partnership and World Health Organization Diagnostic Collaboration Centre. It is FIND’s role to accelerate access to high‐quality diagnostic tools for low‐resource settings and this is achieved by supporting both research and development, and access activities for a wide range of diseases, including COVID‐19. FIND has several clinical research projects to evaluate multiple new diagnostic tests against published Target Product Profiles that have been defined through consensus processes. These studies are for diagnostic products developed by private sector companies who provide access to know‐how, equipment/reagents, and contribute through unrestricted donations as per FIND policy and external SAC review

Julie Domen: no relevant interests; works as a general practitioner

Anouk Tans: none known

Stéphanie Janssens: no relevant interests; works as a general practitioner in training in 'De Wijkpraktijk' in Antwerp

Dakshitha Wickramasinghe: none known

Viktor Lannoy: none known

Sebastiaan Horn: no relevant interests; works as a resident general practitioner: Praktijkhuis Baarle, University of Antwerp, Antwerp, Belgium

Ann Van den Bruel: none known

Figures

1
1
PRISMA flowchart
2
2
Risk of bias and applicability concerns graph: review authors' judgements about each domain presented as percentages across included studies
3
3
Risk of bias and applicability concerns summary: review authors' judgements about each domain for each included study
4
4
Forest plot of upper respiratory tract symptoms
5
5
Forest plot of lower respiratory tract symptoms
6
6
Forest plot of systemic signs and symptoms
7
7
Forest plot of gastrointestinal symptoms
8
8
Forest plot of cardiovascular symptoms (palpitations)
9
9
Forest plot of olfactory symptoms
10
10
Forest plot of multivariable combinations of signs and symptoms
11
11
Summary ROC plot of upper respiratory tract symptoms. The study points (symbols) were scaled according to the sample size
12
12
Summary ROC plot of lower respiratory tract symptoms. The study points (symbols) were scaled according to the sample size
13
13
Summary ROC plot of systemic signs and symptoms. The study points (symbols) were scaled according to the sample size
14
14
Summary ROC plot of gastrointestinal symptoms. The study points (symbols) were scaled according to the sample size
15
15
Summary ROC plot of olfactory symptoms. The study points (symbols) were scaled according to the sample size
16
16
Summary ROC plot of multivariable combinations of signs and symptoms. The study points (symbols) were scaled according to the sample size
17
17
Summary ROC plot of fever by risk of bias concerning participant selection. Summary points and their 95% confidence regions are shown for high and low risk of bias only. The study points (symbols) were scaled according to the sample size
18
18
Summary ROC plot of cough by risk of bias concerning participant selection. Summary points and their 95% confidence regions are shown for high and low risk of bias only. The study points (symbols) were scaled according to the sample size
19
19
Summary ROC plot of anosmia by risk of bias concerning participant selection. Summary points and their 95% confidence regions are shown for high and low risk of bias only. The study points (symbols) were scaled according to the sample size
20
20
Dumbbell plot: olfactory symptoms
21
21
Dumbbell: plot fever. Ordered by age group ‐ children (< 18 years), adults/all ages, older adults (≥ 65 years)
22
22
Dumbbell plot: cough. Ordered by age group ‐ children (< 18 years), adults/all ages, older adults (≥ 65 years)
23
23
Forest plot of upper respiratory signs/symptoms (retrospective data collection)
24
24
Forest plot of lower respiratory signs/symptoms (retrospective data collection)
25
25
Forest plot of systemic signs/symptoms (retrospective data collection)
26
26
Forest plot of cardiovascular signs/symptoms (retrospective data collection)
27
27
Forest plot of gastrointestinal signs/symptoms (retrospective data collection)
28
28
Forest plot of olfactory signs/symptoms (retrospective data collection)
29
29
Forest plot of combinations of signs/symptoms (retrospective data collection)
30
30
Collider bias
1
1. Test
Cough
2
2. Test
Fever
3
3. Test
Dyspnoea
4
4. Test
Sore throat
5
5. Test
Headache
6
6. Test
Diarrhoea
7
7. Test
Myalgia
8
8. Test
Anosmia
9
9. Test
Fatigue
10
10. Test
Chills/shivers
11
11. Test
Chest tightness/pain
12
12. Test
Rhinorrhea
13
13. Test
Ageusia
14
14. Test
Anosmia or ageusia
15
15. Test
Abdominal pain
16
16. Test
Nasal congestion
17
17. Test
Altered mentation/confusion
18
18. Test
Conjunctivitis
19
19. Test
Nausea or vomiting
20
20. Test
Gastrointestinal symptoms (not specified)
21
21. Test
Rash
22
22. Test
Coryza
23
23. Test
Sputum production/productive cough
24
24. Test
Asthenia
25
25. Test
Odynophagia
26
26. Test
Anosmia and ageusia
27
27. Test
Arthralgia
28
28. Test
Vomiting
29
29. Test
Wheeze
30
30. Test
Nausea
31
31. Test
Dry cough
32
32. Test
Malaise
33
33. Test
Enlargement of lymph nodes
34
34. Test
Anosmia or hyposmia
35
35. Test
Anorexia
36
36. Test
Fever (subjective)
37
37. Test
Haemoptysis
38
38. Test
Earache
39
39. Test
Systemic soreness (malaise/myalgia/arthralgia)
40
40. Test
High fever (≥ 38.5 °C)
41
41. Test
Myalgia or arthralgia
42
42. Test
Irritability
43
43. Test
Sneezing
44
44. Test
Anosmia or dysgeusia
45
45. Test
Loss of appetite
46
46. Test
Pulmonary auscultation: crackling bilateral
47
47. Test
Sweating
48
48. Test
Nasal symptoms
49
49. Test
Rhinitis
50
50. Test
Dysgeusia
51
51. Test
SCRiPS score, recent case detection rate
52
52. Test
SCRIPS score, 0.5*recent case detection rate
53
53. Test
Rigors
54
54. Test
Cough or dyspnoea
55
55. Test
Dysuria
56
56. Test
Seizure
57
57. Test
Exanthema
58
58. Test
Exhaustion
59
59. Test
Sinusitis
60
60. Test
Hypoxia
61
61. Test
Multivariable score cut‐off = 5
62
62. Test
Multivariable score cut‐off = 8
63
63. Test
Cough and anosmia
64
64. Test
Fever and anosmia
65
65. Test
Fever and cough and anosmia and dyspnoea and oxygen saturation < 93%
66
66. Test
Fever and dyspnoea
67
67. Test
Anosmia and dyspnoea
68
68. Test
Fever and cough
69
69. Test
Weakness or fatigue
70
70. Test
Palpitations
71
71. Test
Anxiety
72
72. Test
Respiratory distress
73
73. Test
Hyposmia or anosmia
74
74. Test
Diarrhoea and nausea
75
75. Test
Isolated fever
76
76. Test
Myalgia and asthenia and fever
77
77. Test
Cough and fever and sputum production
78
78. Test
Cough and fever and sputum production and dyspnoea
79
79. Test
Isolated headache
80
80. Test
Dyspnoea and cough and fever and low oxygen saturation
81
81. Test
Sore throat and nasal congestion and sneezing and mild fever
82
82. Test
Low body temperature
83
83. Test
Expectoration
84
84. Test
Tachypnoea
85
85. Test
Cyanosis
86
86. Test
Skin lesions
87
87. Test
Rhinitis or pharyngitis
88
88. Test
Dizziness or syncope
89
89. Test
Pulmonary auscultation: crackling unilateral
90
90. Test
CSBSS (cut‐off = 41.7)
91
91. Test
Hyposmia
92
92. Test
Hypogeusia
93
93. Test
Dizziness
94
94. Test
Change to chronic cough
95
95. Test
Dysosmia
96
96. Test
Myalgia and fatigue
97
97. Test
Cough (retrospective data collection)
98
98. Test
Fever (retrospective data collection)
99
99. Test
Dyspnoea (retrospective data collection)
TST-100
TST-100. Test
Sore throat (retrospective data collection)
TST-101
TST-101. Test
Headache (retrospective data collection)
TST-102
TST-102. Test
Diarrhoea (retrospective data collection)
TST-103
TST-103. Test
Myalgia (retrospective data collection)
TST-104
TST-104. Test
Rhinorrhoea (retrospective data collection)
TST-105
TST-105. Test
Chest tightness/pain (retrospective data collection)
TST-106
TST-106. Test
Fatigue (retrospective data collection)
TST-107
TST-107. Test
Anosmia (retrospective data collection)
TST-108
TST-108. Test
Gastrointestinal symptoms not specified (retrospective data collection)
TST-109
TST-109. Test
Nasal congestion (retrospective data collection)
TST-110
TST-110. Test
Nausea or vomiting (retrospective data collection)
TST-111
TST-111. Test
Abdominal pain (retrospective data collection)
TST-112
TST-112. Test
Vomiting (retrospective data collection)
TST-113
TST-113. Test
Myalgia or arthralgia (retrospective data collection)
TST-114
TST-114. Test
Sputum production/productive cough (retrospective data collection)
TST-115
TST-115. Test
Chills/shivers (retrospective data collection)
TST-116
TST-116. Test
Asthenia (retrospective data collection)
TST-117
TST-117. Test
Anosmia or ageusia (retrospective data collection)
TST-118
TST-118. Test
Dysgeusia (retrospective data collection)
TST-119
TST-119. Test
Nausea (retrospective data collection)
TST-120
TST-120. Test
Arthralgia (retrospective data collection)
TST-121
TST-121. Test
Anorexia (retrospective data collection)
TST-122
TST-122. Test
Wheeze (retrospective data collection)
TST-123
TST-123. Test
Haemoptysis (retrospective data collection)
TST-124
TST-124. Test
Respiratory symptoms (not specified; retrospective data collection)
TST-125
TST-125. Test
Skin lesions (retrospective data collection)
TST-126
TST-126. Test
Tachycardia (retrospective data collection)
TST-127
TST-127. Test
Nasal symptoms (retrospective data collection)
TST-128
TST-128. Test
Expectoration (retrospective data collection)
TST-129
TST-129. Test
Ageusia (retrospective data collection)
TST-130
TST-130. Test
Positive auscultation findings (retrospective data collection)
TST-131
TST-131. Test
Tachypnea (retrospective data collection)
TST-132
TST-132. Test
Anosmia/dysosmia or ageusia/dysgeusia (retrospective data collection))
TST-133
TST-133. Test
Earache (retrospective data collection)
TST-134
TST-134. Test
Sneezing (retrospective data collection)
TST-135
TST-135. Test
Dizziness (retrospective data collection)
TST-136
TST-136. Test
Malaise (retrospective data collection)
TST-137
TST-137. Test
Fever (subjective) (retrospective data collection)
TST-138
TST-138. Test
Enlargement of lymph nodes (retrospective data collection)
TST-139
TST-139. Test
Conjunctivitis (retrospective data collection)
TST-140
TST-140. Test
Hypoxia (retrospective data collection)
TST-141
TST-141. Test
Pulmonary auscultation: rhonchi (retrospective data collection)
TST-142
TST-142. Test
Loss of appetite (retrospective data collection)
TST-143
TST-143. Test
Altered mentation/confusion (retrospective data collection)
TST-144
TST-144. Test
Presyncope or syncope (retrospective data collection)
TST-145
TST-145. Test
Stomach ache (retrospective data collection)
TST-146
TST-146. Test
Odynophagia (retrospective data collection)
TST-147
TST-147. Test
Anosmia or dysgeusia (retrospective data collection)
TST-148
TST-148. Test
Weakness or fatigue (retrospective data collection)
TST-149
TST-149. Test
Objective fever (≥ 38 °C) or recent fever/chills (retrospective)
TST-150
TST-150. Test
Body aches or fatigue or dyspnoea or cough or objective fever (≥ 38 °C) or recent fever/chills (retrospective)
TST-151
TST-151. Test
Fatigue or dyspnoea or cough or objective fever (≥ 38 °C) or recent fever/chills (retrospective)
TST-152
TST-152. Test
Dyspnoea or cough or objective fever (≥ 38 °C) or recent fever/chills (retrospective)
TST-153
TST-153. Test
Cough or objective fever (≥ 38 °C) or recent fever/chills (retrospective)
TST-154
TST-154. Test
Recent fever or chills (retrospective data collection)
TST-155
TST-155. Test
Sinusitis (retrospective data collection)
TST-156
TST-156. Test
Systemic soreness (malaise/myalgia/arthralgia) (retrospective)
TST-157
TST-157. Test
Malaise or fatigue (retrospective data collection)
TST-158
TST-158. Test
Lethargy (retrospective data collection)
TST-159
TST-159. Test
Nausea or vomiting or diarrhoea (retrospective data collection)
TST-160
TST-160. Test
Respiratory triage score > 4 (retrospective data collection)
TST-161
TST-161. Test
Respiratory triage score > 5 (retrospective data collection)
TST-162
TST-162. Test
Lower respiratory tract symptoms (retrospective data collection)
TST-163
TST-163. Test
Neurologic symptoms (not specified; retrospective data collection)
TST-164
TST-164. Test
Upper respiratory tract symptoms (retrospective data collection)
TST-165
TST-165. Test
Laryngitis/hoarseness/stridor (retrospective data collection)
TST-166
TST-166. Test
High fever (≥ 38.5 °C) (retrospective data collection)
TST-167
TST-167. Test
Abdominal distention (retrospective data collection)
TST-168
TST-168. Test
Aversion to cold (retrospective data collection)
TST-169
TST-169. Test
Xerostomia (retrospective data collection)
TST-170
TST-170. Test
Hypersomnia (retrospective data collection)
TST-171
TST-171. Test
Hyposmia (retrospective data collection)
TST-172
TST-172. Test
Fever and cough and dyspnoea (retrospective)
TST-173
TST-173. Test
Fever and cough and sore throat (retrospective)
TST-174
TST-174. Test
Fever and cough (retrospective data collection)
TST-175
TST-175. Test
Unconsciousness (retrospective data collection)
TST-176
TST-176. Test
Rash (retrospective data collection)
TST-177
TST-177. Test
Fever or cough or dyspnoea (retrospective data collection)
TST-178
TST-178. Test
Pulmonary auscultation: crackling (retrospective data collection)
TST-179
TST-179. Test
Dysphonia (retrospective data collection)
TST-180
TST-180. Test
Dry cough (retrospective data collection)
TST-181
TST-181. Test
History of fever at home (retrospective data collection)
TST-182
TST-182. Test
Cough or dyspnoea (retrospective data collection)
TST-183
TST-183. Test
Anosmia and dysgeusia (retrospective data collection)
TST-184
TST-184. Test
Palpitations (retrospective data collection)
TST-185
TST-185. Test
Anosmia or hyposmia (retrospective data collection)
TST-186
TST-186. Test
Myalgia or fatigue (retrospective data collection)
TST-187
TST-187. Test
Respiratory distress (retrospective data collection)
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References

References to studies included in this review

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Arenas 2020 {published data only}
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Arslan 2021 {published data only}
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Barbhaya 2021 {published data only}
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Bhattacharya 2021 {published data only}
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Bouzid 2020 {published data only}
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Brendish 2020 {published data only}
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Buonafine 2020 {published data only}
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Chan 2021 {published data only}
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Cheng 2020 {published data only}
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Chew 2021 {published data only}
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Chua 2020 {published data only}
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Chung 2021 {published data only}
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Clemency 2020 {published data only}
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Clifford 2020 {published data only}
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Cunarro‐Lopez 2020 {published data only}
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Drager 2020 {published data only}
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Feng 2021 {published data only}
    1. Feng C, Wang L, Chen X, Zhai Y, Zhu F, Chen H, et al.A novel artificial intelligence-assisted triage tool to aid in the diagnosis of suspected COVID-19 pneumonia cases in fever clinics. Annals of Translational Medicine 2021;9(3):201. [DOI: 10.21037/atm-20-3073] - DOI - PMC - PubMed
Fiel‐Ozores 2021 {published data only}
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Fink 2021 {published data only}
    1. Fink N, Rueckel J, Kaestle S, Schwarze V, Gresser E, Hoppe B, et al.Evaluation of patients with respiratory infections during the first pandemic wave in Germany: characteristics of COVID-19 versus non-COVID-19 patients. BMC Infectious Diseases 2021;21(1):167. [DOI: 10.1186/s12879-021-05829-x] - DOI - PMC - PubMed
Gilbert 2020 {published data only}
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Haehner 2020 {published data only}
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Haliga 2021 {published data only}
    1. Haliga RE, Sorodoc V, Lionte C, Petris OR, Bologa C, Coman AE, et al.Acute clinical syndromes and suspicion of SARS-CoV-2 infection: the experience of a single Romanian center in the early pandemic period. Medicina (Kaunas) 2021;57(2):121. [DOI: 10.3390/medicina57020121] - DOI - PMC - PubMed
Huang 2020 {published data only}
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Hüfner 2020 {published data only}
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Ide 2021 {published data only}
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Ishii 2021 {published data only}
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Jeyashree 2021 {published data only}
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Just 2020 {published data only}
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Kalayjian 2020 {published data only}
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Kelen 2021 {published data only}
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Kempker 2020 {published data only}
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Kim 2020 {published data only}
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King 2020 {published data only}
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Krastinova 2020 {published data only}
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Langer 2020 {published data only}
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Lazzerini 2021 {published data only}
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Leal 2020 {published data only}
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Leung 2021 {published data only}
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Maechler 2020 {published data only}
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Mansella 2020 {published data only}
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Mao 2020 {published data only}
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Martín‐Sánchez 2020 {published data only}
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Martin‐Sanz 2020 {published data only}
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Nazerian 2021 {published data only}
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Nitecki 2021 {published data only}
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O'Reilly 2020a {published data only}
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O'Reilly 2020b {published data only}
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Olivar Lopez 2020 {published data only}
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Peng 2020 {published data only}
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Peyrony 2020 {published data only}
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Pisapia 2020 {published data only}
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Pivetta 2020 {published data only}
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Pokorska‐Śpiewak 2021 {published data only}
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Porto 2021 {published data only}
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Raberahona 2020 {published data only}
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Romero‐Gameros 2020 {published data only}
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Romero‐Gameros 2021 {published data only}
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Rutten 2020a {published data only}
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Rutten 2020b {published data only}
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Sacks 2020 {published data only}
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Saegerman 2021 {published data only}
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Salmon Ceron 2020 {published data only}
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Shah 2020 {published data only}
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Simpson 2020 {published data only}
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Sonoda 2021 {published data only}
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Sun 2020 {published data only}
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Tan 2021 {published data only}
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Tolia 2020 {published data only}
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Tordjman 2020 {published data only}
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Trubiano 2020 {published data only}
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Tudrej 2020 {published data only}
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Van Loon 2021 {published data only}
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Van Walraven 2021 {published data only}
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Vieceli 2020 {published data only}
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Vilke 2020 {published data only}
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Villerabel 2021 {published data only}
    1. Villerabel C, Makinson A, Jaussent A, Picot MC, Nègre-Pagès L, Rouvière JA, et al.Diagnostic value of patient-reported and clinically tested olfactory dysfunction in a population screened for COVID-19. JAMA Otolaryngology–Head & Neck Surgery 2021;147(3):271-9. [DOI: 10.1001/jamaoto.2020.5074] - DOI - PMC - PubMed
Wee 2020 {published data only}
    1. Wee LE, Chan YZ, Teo NY, Cherng BZ, Thien SY, Wong M, et al.The role of self-reported olfactory and gustatory dysfunction as a screening criterion for suspected COVID-19. European Archives of Oto-Rhino-Laryngology 2020;277(8):2389-90. [DOI: 10.1007/s00405-020-05999-5] - DOI - PMC - PubMed
Wei 2020 {published data only}
    1. Wei Y, Lu Y, Xia L, Yuan X, Li G, Li X, et al.Analysis of 2019 novel coronavirus infection and clinical characteristics of outpatients: an epidemiological study from a fever clinic in Wuhan, China. Journal of Medical Virology 2020;92:2758-67. - PMC - PubMed
Wernhart 2020 {published data only}
    1. Wernhart S, Förster TH, Weihe E.Outpatient management of oligosymptomatic patients with respiratory infection in the era of SARS-CoV-2: experience from rural German general practitioners. BMC Infectious Diseases 2020;20(1):811. [DOI: 10.1186/s12879-020-05538-x] - DOI - PMC - PubMed
Xie 2020 {published data only}
    1. Xie S, Zhang G, Yu H, Wang J, Wang S, Tang G, et al.The epidemiologic and clinical features of suspected and confirmed cases of imported 2019 novel coronavirus pneumonia in north Shanghai, China. Annals of Translational Medicine 2020;8(10):637. - PMC - PubMed
Yombi 2020 {published data only}
    1. Yombi JC, De Greef J, Marsin A-S, Simon A, Rodriguez-Villalobos H, Penaloza A, et al.Symptom-based screening for COVID-19 in health care workers: the importance of fever. Journal of Hospital Infection 2020;105(3):428-9. - PMC - PubMed
Yonker 2020 {published data only}
    1. Yonker LM, Neilan AM, Bartsch Y, Patel AB, Regan J, Arya P, et al.Pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): clinical presentation, infectivity, and immune responses. Journal of Pediatrics 2020;227:45–52.e5. [DOI: 10.1016/j.jpeds.2020.08.037] - DOI - PMC - PubMed
Zayet 2020a {published data only}
    1. Zayet S, Klopfenstein T, Mercier J, Kadiane-Oussou NJ, Lan Cheong Wah L, Royer PY, et al.Contribution of anosmia and dysgeusia for diagnostic of COVID-19 in outpatients. Infection 2020;14:1-5. - PMC - PubMed
Zhu 2020 {published data only}
    1. Zhu W, Xie K, Lu H, Xu L, Zhou S, Fang S.Initial clinical features of suspected coronavirus disease 2019 in two emergency departments outside of Hubei, China. Journal of Medical Virology 2020;92(9):1525-32. [DOI: 10.1002/jmv.25763 ] - PMC - PubMed
Zimmerman 2020 {published data only}
    1. Zimmerman RK, Nowalk MP, Bear T, Taber R, Clarke KS, Sax TM, et al.Proposed clinical indicators for efficient screening and testing for COVID-19 infection using Classification and Regression Trees (CART) analysis. Human Vaccines & Immunotherapeutics 2020;17(4):1109-12. [DOI: ] - PMC - PubMed
Zurl 2021 {published data only}
    1. Zurl C, Eber E, Siegl A, Loeffler S, Stelzl E, Kessler HH, et al.Low rate of SARS-CoV-2 infections in symptomatic patients attending a pediatric emergency department. Frontiers in Pediatrics 2021;9:637167. [DOI: 10.3389/fped.2021.637167] - DOI - PMC - PubMed

References to studies excluded from this review

Accorsi 2020 {published data only}
    1. Accorsi TA, Amicis K, Brígido AR, Belfort DS, Habrum FC, Scarpanti FG, et al.Assessment of patients with acute respiratory symptoms during the COVID-19 pandemic by Telemedicine: clinical features and impact on referral. Einstein (Sao Paulo) 2020;18:eAO6106. [DOI: 10.31744/einstein_journal/2020AO6106] - DOI - PMC - PubMed
Afshar 2020 {published data only}
    1. Afshar Y, Gaw SL, Flaherman VJ, Chambers BD, Krakow D, Berghella V, et al.Clinical presentation of coronavirus disease 2019 (COVID-19) in pregnant and recently pregnant people. Obstetrics and Gynecology 2020;136(6):1117-25. [DOI: 10.1097/AOG.0000000000004178] - DOI - PMC - PubMed
Agarwal 2021 {published data only}
    1. Agarwal R, Gupta E, Dubey S, Padhi A, Khodare A, Kumar G, et al.Pooled nasopharyngeal swab collection in a single vial for the diagnosis of SARS CoV-2 infection: an effective cost saving method. Indian Journal of Medical Microbiology 2021;39(2):231-4. [DOI: 10.1016/j.ijmmb.2020.11.002] - DOI - PMC - PubMed
Ai 2020 {published data only}
    1. Ai JW, Zhang HC, Xu T, Wu J, Zhu M, Yu YQ, et al.Optimizing diagnostic strategy for novel coronavirus pneumonia, a multi-center study in Eastern China. medRxiv [Preprint] 2020. [DOI: ]
Akinbami 2021 {published data only}
    1. Akinbami LJ, Petersen LR, Sami S, Vuong N, Lukacs SL, Mackey L, et al.COVID-19 symptoms and SARS-CoV-2 antibody positivity in a large survey of first responders and healthcare personnel, May-July 2020. Clinical Infectious Diseases 2021;73(3):e822-5. [DOI: 10.1093/cid/ciab080] - DOI - PMC - PubMed
Akyala 2020 {published data only}
    1. Akyala AI, Awayimbo JR, Elayo MI, Olugbade OT, Akabe EA, Akinyoade A.Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among health care workers in Nasarawa State, Nigeria: implications for infection prevention and control measures. Pan African Medical Journal 2020;37 Suppl 1:21. [DOI: 10.11604/pamj.supp.2020.37.21.25767] - DOI - PMC - PubMed
Aleebrahim‐Dehkordi 2020 {published data only}
    1. Aleebrahim-Dehkordi E, Reyhanian A, Hasanpour-Dehkordi A.Clinical manifestation and the risk of exposure to SARS-CoV-2 (COVID-19). International Journal of Preventive Medicine 2020;11:86. [DOI: 10.4103/ijpvm.IJPVM_145_20] - DOI - PMC - PubMed
Al‐Rifai 2021 {published data only}
    1. Al-Rifai RH, Acuna J, Al Hossany FI, Aden B, Al Memari SA, Al Mazrouei SK, et al.Epidemiological characterization of symptomatic and asymptomatic COVID-19 cases and positivity in subsequent RT-PCR tests in the United Arab Emirates. PLoS One 2021;16(2):e0246903. [DOI: 10.1371/journal.pone.0246903] - DOI - PMC - PubMed
Altınbilek 2020 {published data only}
    1. Altınbilek E, Öztürk D, Atasoy C, Özlem M, Yılmaz F, Kavalci C.Analysis of the patients who admitted to a Turkish emergency department during COVID-19 pandemic. Acta Biomedica 2020;91(4):e2020201. [DOI: 10.23750/abm.v91i4.10227] - DOI - PMC - PubMed
Andina‐Martinez 2021 {published data only}
    1. Andina-Martinez D, Nieto-Moro M, Alonso-Cadenas JA, Añon-Hidalgo J, Hernandez-Martin A, Perez-Suarez E, et al.Mucocutaneous manifestations in children hospitalized with COVID-19. Journal of the American Academy of Dermatology 2021;85(1):88-94. [DOI: 10.1016/j.jaad.2021.03.083] - DOI - PMC - PubMed
Antonelli 2021 {published data only}
    1. Antonelli M, Capdevila J, Chaudhari A, Granerod J, Canas LS, Graham MS, et al.Optimal symptom combinations to aid COVID-19 case identification: analysis from a community-based, prospective, observational cohort. Journal of Infection 2021;82(3):384-90. [DOI: 10.1016/j.jinf.2021.02.015] - DOI - PMC - PubMed
Aubert 2021 {published data only}
    1. Aubert J, Durán D, Monsalves MJ, Rodríguez MF, Rotarou ES, Gajardo J, et al.Diagnostic properties of case definitions of suspected COVID-19 in Chile, 2020 [Propiedades diagnósticas de las definiciones de caso sospechoso de COVID-19 en Chile, 2020]. Revista Panamericana de Salud Publica [Pan American Journal of Public Health] 2021;45:e14. [DOI: 10.26633/RPSP.2021.14] - DOI - PMC - PubMed
Auvinen 2021 {published data only}
    1. Auvinen R, Nohynek H, Syrjänen R, Ollgren J, Kerttula T, Mäntylä J, et al.Comparison of the clinical characteristics and outcomes of hospitalized adult COVID-19 and influenza patients - a prospective observational study. Infectious Diseases 2021;53(2):111-21. [DOI: 10.1080/23744235.2020.1840623] - DOI - PubMed
Baghaei 2020 {published data only}
    1. Baghaei P, Nadji SA, Marjani M, Moniri A, Hashemian SM, Sheikhzade H, et al.Clinical manifestations of patients with coronavirus disease 2019 (COVID-19) in a referral center in Iran. Tanaffos 2020;19(2):122-8. - PMC - PubMed
Bailey 2020 {published data only}
    1. Bailey L, O'Donoghue A, Martin A.Acute presentations of nursing home residents to hospital during COVID-19 pandemic. European Geriatric Medicine 2020;11 Suppl 1:S52.
Bailey 2021 {published data only}
    1. Bailey LC, Razzaghi H, Burrows EK, Bunnell HT, Camacho PE, Christakis DA, et al.Assessment of 135 794 pediatric patients tested for severe acute respiratory syndrome coronavirus 2 across the United States. JAMA Pediatrics 2021;175(2):176-84. - PMC - PubMed
Bartlett 2020 {published data only}
    1. Bartlett B, Ploog N, Heaton H, Mullan A, Knutson B.287 likelihood of COVID-19 positive test results in patients who present to the emergency department with key COVID chief symptoms. Annals of Emergency Medicine 2020;76(4):S111. [DOI: 10.1016/j.annemergmed.2020.09.301] - DOI
Bastiani 2021 {published data only}
    1. Bastiani L, Fortunato L, Pieroni S, Bianchi F, Adorni F, Prinelli F, et al.Rapid COVID-19 screening based on self-reported symptoms: psychometric assessment and validation of the EPICOVID19 Short Diagnostic Scale. Journal of Medical Internet Research 2021;23(1):e23897. - PMC - PubMed
Bhatta 2021 {published data only}
    1. Bhatta S, Gandhi S, Saindani SJ, Ganesuni D, Ghanpur AD.Otorhinolaryngological manifestations of coronavirus disease 2019: a prospective review of 600 patients. Journal of Laryngology and Otology 2021;135(3):206-11. - PMC - PubMed
Bidkar 2021 {published data only}
    1. Bidkar V, Mishra M, Selvaraj K, Joshi P, Shrikrishna BH, Dabhekar S, et al.Testing olfactory and gustatory dysfunctions among quarantine COVID-19 suspects. Indian Journal of Otolaryngology and Head & Neck Surgery 2021;73(3):304-9. - PMC - PubMed
Bonadio 2020 {published data only}
    1. Bonadio W, Bonadio W, Jackson K, Gottlieb L.379 accuracy of an emergency department clinical protocol for early identification of coronavirus infection. Annals of Emergency Medicine 2020;76(4):S146. - PMC - PubMed
Brotons 2020 {published data only}
    1. Brotons C, Serrano J, Fernández D, Garcia-Ramos C, Ichazo B, Lemaire J, et al.Seroprevalence against COVID-19 and follow-up of suspected cases in primary health care in Spain. medRxiv [Preprint]. [DOI: ] - PubMed
Burrel 2021 {published data only}
    1. Burrel S, Hausfater P, Dres M, Pourcher V, Luyt CE, Teyssou E, et al.Co-infection of SARS-CoV-2 with other respiratory viruses and performance of lower respiratory tract samples for the diagnosis of COVID-19. International Journal of Infectious Diseases 2021;102:10-3. - PMC - PubMed
Cadegiani 2021 {published data only}
    1. Cadegiani FA, Zimerman RA, Campello de Souza B, McCoy J, Pereira E, Costa RA, et al.The AndroCoV Clinical Scoring for COVID-19 Diagnosis: a prompt, feasible, costless, and highly sensitive diagnostic tool for COVID-19 based on a 1757-patient cohort. Cureus 2021;13(1):e12565. - PMC - PubMed
Cai 2020 {published data only}
    1. Cai X, Jiang H, Zhang S, Xia S, Du W, Ma Y, et al.Clinical manifestations and pathogen characteristics in children admitted for suspected COVID-19. Frontiers of Medicine 2020;14(6):776-85. - PMC - PubMed
Calagnan 2020 {published data only}
    1. Calagnan E, Gobbato M, Burba I, Del Zotto S, Toffolutti F, Serraino D, et al.COVID-19 infections in the Friuli Venezia Giulia Region (northern Italy): a population-based retrospective analysis. Epidemiologia & Prevenzione 2020;44(5-6 Suppl 2):323-9. - PubMed
Carignan 2020 {published data only}
    1. Carignan A, Valiquette L, Grenier C, Musonera JB, Nkengurutse D, Marcil-Héguy A, et al.Anosmia and dysgeusia associated with SARS-CoV-2 infection: an age-matched case-control study. CMAJ 2020;192(26):E702-7. - PMC - PubMed
Challener 2020 {published data only}
    1. Challener DW, Challener GJ, Gow-Lee VJ, Fida M, Shah AS, O'Horo JC.Screening for COVID-19: patient factors predicting positive PCR test. Infection Control and Hospital Epidemiology 2020;41(8):968-9. - PMC - PubMed
Chen 2020 {published data only}
    1. Chen X, Tang Y, Mo Y, Li S, Lin D, Yang Z, et al.A diagnostic model for coronavirus disease 2019 (COVID-19) based on radiological semantic and clinical features: a multi-center study. European Radiology 2020;30(9):4893-902. - PMC - PubMed
Chen 2021 {published data only}
    1. Chen R, Xu G, Yang L, Deng Z, Hu Q, Hu H, et al.A new rapid screening program based on risk scores for COVID-19 patients. Internal and Emergency Medicine 2021;16(4):925-32. - PMC - PubMed
Concheiro‐Guisan 2020 {published data only}
    1. Concheiro-Guisan A, Fiel-Ozores A, Novoa-Carballal R, González-Duran ML, Portugués de la Red M, Martínez-Reglero C, et al.Subtle olfactory dysfunction after SARS-CoV-2 virus infection in children. International Journal of Pediatric Otorhinolaryngology 2020;140:110539. - PMC - PubMed
D'Souza 2020 {published data only}
    1. D'Souza G, Springer G, Gustafson D, Kassaye S, Alcaide M L, Ramirez C, et al.COVID-19 symptoms and SARS-CoV-2 infection among people living with HIV in the US: the MACS/WIHS combined cohort study. HIV Research & Clinical Practice 2020;21(5):130-9. - PMC - PubMed
Dai 2021 {published data only}
    1. Dai YN, Zheng W, Wu QQ, Hui TC, Sun NN, Chen GB, et al.A rapid screening model for early predicting novel coronavirus pneumonia in Zhejiang Province of China: a multicenter study. Scientific Reports 2021;11(1):3863. - PMC - PubMed
Dantas 2021 {published data only}
    1. Dantas LF, Peres IT, Bastos LS, Marchesi JF, Souza GF, Gelli JG, et al.App-based symptom tracking to optimize SARS-CoV-2 testing strategy using machine learning. PLoS One 2021;16(3):e0248920. - PMC - PubMed
De Angelis 2020 {published data only}
    1. De Angelis G, Posteraro B, Biscetti F, Ianiro G, Zileri Dal Verme L, Cattani P, et al.Confirmed or unconfirmed cases of 2019 novel coronavirus pneumonia in Italian patients: a retrospective analysis of clinical features. BMC Infectious Diseases 2020;20(1):775. - PMC - PubMed
Deng 2020 {published data only}
    1. Deng LS, Yuan J, Ding L, Chen YL, Zhao CH, Chen GQ, et al.Comparison of patients hospitalized with COVID-19, H7N9 and H1N1. Infectious Diseases of Poverty 2020;9(1):163. - PMC - PubMed
Dixon 2021 {published data only}
    1. Dixon BE, Wools-Kaloustian KK, Fadel WF, Duszynski TJ, Yiannoutsos C, Halverson PK, et al.Symptoms and symptom clusters associated with SARS-CoV-2 infection in community-based populations: results from a statewide epidemiological study. PLoS One 2021;16(3):e0241875. - PMC - PubMed
Dreyer 2020 {published data only}
    1. Dreyer NA, Reynolds M, DeFilippo Mack C, Brinkley E, Petruski-Ivleva N, Hawaldar K, et al.Self-reported symptoms from exposure to COVID-19 provide support to clinical diagnosis, triage and prognosis: an exploratory analysis. Travel Medicine and Infectious Disease 2020;38:101909. - PMC - PubMed
Duan 2020 {published data only}
    1. Duan J, Liang M, Li Y, Wu D, Chen Y, Gao S, et al.Definition and retrospective application of a clinical scoring system for COVID-19 triage at presentation. Therapeutic Advances in Respiratory Disease 2020;14:1753466620963019. - PMC - PubMed
Duque 2021 {published data only}
    1. Duque MP, Lucaccioni H, Costa C, Marques R, Antunes D, Hansen L, et al.COVID-19 symptoms: a case-control study, Portugal, March-April 2020. Epidemiology and Infection 2021;149:e54. - PMC - PubMed
Duramaz 2021 {published data only}
    1. Duramaz BB, Turel O, Korkmaz C, Karadogan MT, Yozgat CY, Iscan A, et al.A snapshot of pediatric patients with COVID-19 in a pandemic hospital. Klinische Pädiatrie 2021;233(1):24-30. - PubMed
Elimian 2020 {published data only}
    1. Elimian KO, Ochu CL, Ebhodaghe B, Myles P, Crawford EE, Igumbor E, et al.Patient characteristics associated with COVID-19 positivity and fatality in Nigeria: retrospective cohort study. BMJ Open 2020;10(12):e044079. - PMC - PubMed
Escosteguy 2020 {published data only}
    1. Escosteguy CC, Eleuterio TA, Pereira AG, Marques MR, Brandão AD, Batista JP.COVID-19: a cross-sectional study of suspected cases admitted to a federal hospital in Rio de Janeiro, Brazil, and factors associated with hospital death. Epidemiologia e Serviços de Saúde 2020;30(1):e2020750. - PubMed
Feehan 2021 {published data only}
    1. Feehan AK, Fort D, Velasco C, Burton JH, Garcia-Diaz J, Price-Haywood EG, et al.The importance of anosmia, ageusia and age in community presentation of symptomatic and asymptomatic SARS-CoV-2 infection in Louisiana, USA; a cross-sectional prevalence study. Clinical Microbiology and Infection 2021;27(4):633.e9-16. - PMC - PubMed
Fisher 2021 {published data only}
    1. Fisher KA, Olson SM, Tenforde MW, Self WH, Wu M, Lindsell CJ, et al.Symptoms and recovery among adult outpatients with and without COVID-19 at 11 healthcare facilities-July 2020, United States. Influenza and Other Respiratory Viruses 2021;15(3):345-51. - PMC - PubMed
Foster 2021 {published data only}
    1. Foster CE, Marquez L, Davis AL, Tocco E, Koy TH, Dunn J, et al.A surge in pediatric coronavirus disease 2019 cases: the experience of Texas Children's Hospital from March to June 2020. Journal of the Pediatric Infectious Diseases Society 2021;10(5):593-8. - PMC - PubMed
Gale 2020 {published data only}
    1. Gale J, Clark DA, Bohm C, Canney M, Davis I, LeBlanc JJ, et al.COVID-19 status, symptom burden, and characteristics of dialysis patients residing in areas of community transmission: research letter. Canadian Journal of Kidney Health and Disease 2020;7:2054358120964178. - PMC - PubMed
Gerkin 2021 {published data only}
    1. Gerkin RC, Ohla K, Veldhuizen MG, Joseph PV, Kelly CE, Bakke AJ, et al.Recent smell loss is the best predictor of COVID-19 among individuals with recent respiratory symptoms. Chemical Sense 2021;46:bjaa081. - PMC - PubMed
Giavedoni 2020 {published data only}
    1. Giavedoni P, Podlipnik S, Pericàs JM, Fuertes de Vega I, García-Herrera A, Alós L, et al.Skin manifestations in COVID-19: prevalence and relationship with disease severity. Journal of Clinical Medicine 2020;9(10):3261. - PMC - PubMed
Gibbons 2021 {published data only}
    1. Gibbons C, Hussain M, O'Keeffe DT, Simpkin AJ.An analysis of patient self-reported COVID-19 symptoms during the first wave of the pandemic in Ireland. Irish Journal of Medical Science 2021 Mar 25 [Epub ahead of print]. - PMC - PubMed
Gnanasambantham 2020 {published data only}
    1. Gnanasambantham K, Aitken G, Morris B, Simionato J, Chua EH, Ibrahim JE.Developing a clinical screening tool for identifying COVID-19 infection in older people dwelling in residential aged care services. Australasian Journal on Ageing 2020;40(1):48-57. - PubMed
Goel 2020 {published data only}
    1. Goel A, Raizada A, Bansal K, Gaur N, Abraham J, Yadav A.Profile of patients suspected to be COVID-19: a retrospective analysis of early pandemic data. Cureus 2020;12(8):e10125. - PMC - PubMed
Gombos 2021 {published data only}
    1. Gombos K, Földi M, Kiss S, Herczeg R, Gyenesei A, Geiger L, et al.Analysis of COVID-19-related RT-qPCR test results in Hungary: epidemiology, diagnostics, and clinical outcome. Frontiers in Medicine 2021;7:625673. - PMC - PubMed
Goodacre 2020 {published data only}
    1. Goodacre S, Thomas B, Lee E, Sutton L, Loban A, Waterhouse S, et al.Characterisation of 22445 patients attending UK emergency departments with suspected COVID-19 infection: observational cohort study. PLoS One 2020;15(11):e0240206. - PMC - PubMed
Guillén 2020 {published data only}
    1. Martínez AG, Gálvez MA, Rodriguez Sanz S, Hernandez Ruiz P, García Morillas A, Sánchez ET.Incidence of smell and taste disorders and associated factors in patients with mild to moderate COVID-19. Polish Journal of Otolaryngology 2020;75(2):1-5. - PubMed
Gurrola 2021 {published data only}
    1. Gurrola JG 2nd, Chang JL, Roland LT, Loftus PA, Cheung SW.Short-term chemosensory distortions and phantoms in COVID-19. Laryngoscope Investigative Otolaryngology 2021;6(2):172-6. - PMC - PubMed
Haddadin 2021 {published data only}
    1. Haddadin Z, Chappell J, McHenry R, Pulido CG, Rahman H, Gu W, et al.Coronavirus surveillance in a pediatric population in Jordan from 2010 to 2013: a prospective viral surveillance study. Pediatric Infectious Disease Journal 2021;40(1):e12-e7. - PubMed
Hamed 2021 {published data only}
    1. Hamed E, Alnuaimi AS, Syed MA, Elhamid MA, Sedeeq ST, Alemrayat B, et al.Clinical characteristics of 51815 patients presenting with positive and negative SARS-CoV-2 swab results in primary health care settings. Journal of Infection 2021;82(4):84-123. - PMC - PubMed
Hernández‐Cruz 2021 {published data only}
    1. Hernández-Cruz RG, Sánchez-Cobo D, Acevedo-Gallegos S, Helguera-Repetto AC, Rodriguez-Bosch MR, Ramirez-Santes VH, et al.Clinical characteristics and risk factors for SARS-CoV-2 infection in pregnant women attending a third level reference center in Mexico City. Journal of Maternal-fetal & Neonatal Medicine 2021:1-5. - PubMed
Hosseinzadeh 2021 {published data only}
    1. Hosseinzadeh A, Rezapour M, Rohani-Rasaf M, Emamian MH, Talebi S, Goli S, et al.Epidemiological patterns of syndromic symptoms in suspected patients with covid-19 in Iran: a latent class analysis. Journal of Research in Health Sciences 2021;21(1):e00508. - PMC - PubMed
Hosseninasab 2020 {published data only}
    1. Hosseninasab A, Bafti MS, Ebrahimi S, Anjomshoaa A, Zerandi FS, Jafari M, et al.Coronavirus disease 2019 in children with acute respiratory infection: a study from southeastern Iran. Shiraz E Medical Journal 2020;21(12):1-7.
Hubiche 2021 {published data only}
    1. Hubiche T, Phan A, Leducq S, Rapp J, Fertitta L, Aubert H, et al.Acute acral eruptions in children during the COVID-19 pandemic: characteristics of 103 children and their family clusters. Annales de Dermatologie et de Vénéréologie 2021;148(2):94-100. - PMC - PubMed
Hurst 2020 {published data only}
    1. Hurst JH, Heston SM, Chambers HN, Cunningham HM, Price MJ, Suarez L, et al.SARS-CoV-2 infections among children in the Biospecimens from Respiratory Virus-Exposed Kids (BRAVE Kids) Study. Clinical Infectious Diseases 2020 Nov 03 [Epub ahead of print]. - PMC - PubMed
Indini 2021 {published data only}
    1. Indini A, Cattaneo M, Ghidini M, Rijavec E, Bareggi C, Galassi B, et al.Triage process for the assessment of coronavirus disease 2019-positive patients with cancer: the ONCOVID prospective study. Cancer 2021;127(7):1091-101. - PMC - PubMed
Islam 2020 {published data only}
    1. Islam N, Ara Rahman M, Uz Zaman A, Ferdous N, Bin Nazrul F, Tuz Zahura F, et al.Frequency and characteristics of COVID-19 infection in rheumatic patients-an online survey from Bangladesh. International Journal of Rheumatic Diseases 2020;23 Suppl 1:171.
Jain 2021 {published data only}
    1. Jain A, Kaur J, Rai AK, Pandey AK.Anosmia: a clinical indicator of COVID-19 reinfection. Ear, Nose, & Throat Journal 2021;100(2 Suppl):180S-181S. - PubMed
Karni 2020 {published data only}
    1. Karni N, Klein H, Asseo K, Benjamini Y, Israel S, Nammary M, et al.Self-rated smell ability enables highly specific predictors of COVID-19 status: a case-control study in Israel. Open Forum Infectious Diseases 2020;8(2):ofaa589. - PMC - PubMed
Kasiukiewicz 2020 {published data only}
    1. Kasiukiewicz A, Wojszel ZB, Kazberuk M, Sitkiewicz J, Olszewska J.Symptoms and final diagnoses of patients referred to one of the COVID-19 dedicated hospitals in Poland - a cross-sectional study. European Geriatric Medicine 2020;11 Suppl 1:S83.
Kline 2021 {published data only}
    1. Kline JA, Camargo CA, Courtney DM, Kabrhel C, Nordenholz KE, Aufderheide T, et al.Clinical prediction rule for SARS-CoV-2 infection from 116 U.S. emergency departments 2-22-2021. PLoS One 2021;16(3):e0248438. - PMC - PubMed
Lechner 2021 {published data only}
    1. Lechner M, Liu J, Counsell N, Ta NH, Rocke J, Anmolsingh R, et al.Course of symptoms for loss of sense of smell and taste over time in one thousand forty-one healthcare workers during the COVID-19 pandemic: our experience. Clinical Otolaryngology 2021;46(2):451-7. - PMC - PubMed
Lee 2020 {published data only}
    1. Lee DJ, Lockwood J, Das P, Wang R, Grinspun E, Lee JM.Self-reported anosmia and dysgeusia as key symptoms of coronavirus disease 2019. CJEM 2020;22(5):1-8. - PMC - PubMed
Lee 2021 {published data only}
    1. Lee DJ, Daliyot D, Wang R, Lockwood J, Das P, Zimlichman E, et al.Comparative study of chemosensory dysfunction in COVID-19 in 2 geographically distinct regions. Ear, Nose & Throat Journal 2021:1455613211000170. - PubMed
Li 2020a {published data only}
    1. Li Y, Li H, Han J, Yang L.The preliminary comparative results between COVID-19 and non-COVID-19 patients in western China. BMC Infectious Diseases 2020;20(1):935. - PMC - PubMed
Li 2020b {published data only}
    1. Li Y, Shang Y, Yang Y, Wang M, Yu D, Su D, et al.Factors associated with a positive severe acute respiratory syndrome coronavirus 2 testing in suspected cases presenting with pneumonia: a retrospective cohort study in a single medical center. Respiration 2020;99(9):739-47. - PubMed
Li 2021 {published data only}
    1. Li S, Liu SY, Zhao YQ, Li QY, Liu DY, Liu ZC, et al.Spatial and temporal distribution and predictive value of chest CT scoring in patients with COVID-19. Zhonghua Jie He He Hu Xi Za Zhi 2021;44(3):230-6. - PubMed
Liang 2020 {published data only}
    1. Liang Y, Liang J, Zhou Q, Li X, Lin F, Deng Z, et al.Prevalence and clinical features of 2019 novel coronavirus disease (COVID-19) in the fever clinic of a teaching hospital in Beijing: a single-center, retrospective study. medRxiv [Preprint]. [DOI: ]
Liu 2021 {published data only}
    1. Liu Y, Chen H, Tan W, Kuang Y, Tang K, Luo Y, et al.Clinical characteristics and outcome of SARS-CoV-2 infection during pregnancy. Journal of Infection 2021;82(6):e9-10. - PMC - PubMed
Loftus 2020 {published data only}
    1. Loftus PA, Roland LT, Gurrola JG 2nd, Cheung SW, Chang JL.Temporal profile of olfactory dysfunction in COVID-19. OTO Open 2020;4(4):2473974X20978133. - PMC - PubMed
Lu 2020 {published data only}
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References to other published versions of this review

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