Otolaryngology–Head and Neck Surgery

Volume 165, Issue 1 p. 33-42

Review Articles

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Prevalence and Characteristics of Taste Disorders in Cases of COVID-19: A Meta-analysis of 29,349 Patients

Jeyasakthy Saniasiaya MD, MMed,

Jeyasakthy Saniasiaya MD, MMed

Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

These authors contributed equally to this article.

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Md Asiful Islam PhD,

Md Asiful Islam PhD

Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia

These authors contributed equally to this article.

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Baharudin Abdullah MBBS, MMed,

Corresponding Author

Baharudin Abdullah MBBS, MMed

[email protected]

Department of Otorhinolaryngology–Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia

Baharudin Abdullah, MBBS, MMed, Department of Otorhinolaryngology–Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Kelantan 16150, Malaysia. Email: [email protected]Search for more papers by this author

Jeyasakthy Saniasiaya MD, MMed,

Jeyasakthy Saniasiaya MD, MMed

Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia

These authors contributed equally to this article.

Search for more papers by this author

Md Asiful Islam PhD,

Md Asiful Islam PhD

Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia

These authors contributed equally to this article.

Search for more papers by this author

Baharudin Abdullah MBBS, MMed,

Corresponding Author

Baharudin Abdullah MBBS, MMed

[email protected]

Department of Otorhinolaryngology–Head and Neck Surgery, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia

First published: 15 December 2020

https://doi.org/10.1177/0194599820981018

Citations: 4

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Abstract

Objective

The purpose of this meta-analysis is to assess the pooled prevalence of taste disorders and their subtypes in patients with COVID-19.

Data Sources

PubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between December 1, 2019, and June 23, 2020, without language restrictions. There was no restriction on the study design; therefore, observational studies, clinical trials, and case series were included. In addition, preprints were considered if data of interest were reported.

Review Methods

Two authors independently screened articles for eligibility. A random effects model was used to estimate the pooled prevalence with 95% CIs. Quality assessment was done with critical appraisal tools of the Joanna Briggs Institute. The robustness of the pooled estimates was checked by subgroup and sensitivity analyses.

Results

Fifty-nine studies were included (N = 29,349 patients, 64.4% female). The pooled prevalence of taste disorders in patients with COVID-19 was 48.1% (95% CI, 41.3%-54.8%). The prevalence of taste disorders in studies with objective assessments was higher as compared with subjective assessments (59.2% vs 47.3%). The disorders were observed in 55.2% of European patients; 61.0%, North American; 27.1%, Asian; 29.5%, South American; and 25.0%, Australian. Ageusia, hypogeusia, and dysgeusia were detected in 28.0%, 33.5%, and 41.3% of patients with COVID-19. We identified 91.5% of the included studies as high quality.

Conclusions

The prevalence of taste disorders in patients with COVID-19 was 48.1%. Objective assessments have higher prevalence than subjective assessments. Dysgeusia is the most common subtype, followed by ageusia and hypogeusia.

The coronavirus disease 2019 (COVID-19) infection, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first reported in Hubei province in Wuhan, China, in December 2019 and has since spread globally.¹ Atypical presentations, including smell or olfactory disorder (ie, anosmia, hyposmia, and dysosmia) and taste or gustatory disorder (ie, ageusia, hypogeusia, and dysgeusia), are not a sine qua non symptom of COVID-19. The Centers for Disease Control and Prevention recently added new onset of smell and taste loss to its chief symptoms that may suggest SARS-CoV-2 infection—besides cough, shortness of breath, fever, chills, muscle pain, and sore throat.² Interestingly, only a meager number of cases involving smell and taste disorders have been reported among the Asian population, particularly China. An earlier report by Mao et al³ revealed hypogeusia in 5.6% of patients with COVID-19 and hyposmia in 5.1%, whereas a multicenter European study revealed 88.0% with taste dysfunction and 85.6% with olfactory dysfunction.⁴

Researchers have unveiled that the variation in clinical manifestation across different populations worldwide is attributed to the mutation found on the genome sequences of the virus.⁵ Coronaviruses are single-stranded RNA viruses well known for their expeditious nature of mutation as well as recombination.⁶ A recent meta-analysis by Aziz et al⁷ based on 5 studies demonstrated the prevalence of taste disorders in 49.8% of patients with COVID-19. Due to the limited data available, the authors cautioned that their results have a high heterogeneity rate and might have some degree of bias. Furthermore, the situation is rapidly evolving, and there are new available studies that can be appraised with the previous ones. Given this, a better design and robust meta-analysis are essential to reassess and depict the association of taste disorders with COVID-19 infection.

Olfactory dysfunction is by now regarded as one key or important symptom ensuing the increasing evidence of its association with SARS-CoV-2 infection.^8-10 Interestingly, taste dysfunction has been linked to retronasal olfactory dysfunction rather than diminished gustation itself.¹¹ Recent data, however, suggested that taste dysfunction is an independent manifestation rather than part of a retronasal trajectory.¹² The SARS-CoV-2 distinctive tendency to cause selective neurologic impairment may explain the different presentation of taste and olfactory dysfunction,⁴ but this may also be due to different methodologies from studies reporting different rates of chemosensory disturbance. We hypothesize that new onset of taste disorder is an early clinical presentation of COVID-19 infection. We performed a comprehensive systematic review and meta-analysis of the currently available literature to outline the prevalence of taste disorders in patients with COVID-19.

Methods

Systematic Review Protocol

We conducted a systematic review and meta-analysis of the literature in accordance with the PRISMA guideline to identify studies that reported the prevalence of taste disorders in patients with COVID-19 worldwide.¹³ The protocol of this study was registered with the International Prospective Register of Systematic Reviews database (PROSPERO: CRD42020188384).

Eligibility Criteria

The objective was to identify studies published during the COVID-19 outbreak that presented the prevalence of taste disorders in patients with COVID-19 worldwide. There was no restriction on the study design; therefore, observational studies, clinical trials, and case series were included. In addition to the published studies, preprints were considered if data of interest were reported. Review articles, case reports, opinions, and perspectives were excluded. Data reported by news reports and press releases or data collected from websites or databases were not considered.

Search Strategy

PubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between December 1, 2019, and June 23, 2020, without language restrictions. The following key terms were searched: coronavirus, COVID-19, COVID19, nCoV, SARS-CoV-2, SARS-CoV2, taste, gustatory, ageusia, hypogeusia, dysgeusia, and parageusia. Complete details of the search strategy are in Supplemental Table S1 (available online). To ensure a robust search procedure, references of the included studies were also reviewed. Duplicate studies were excluded by using EndNote X8 software.

Study Selection

To identify eligible studies, 2 authors (J.S. and M.A.I.) independently screened articles of interest by title and abstract, followed by full text. Disagreements about inclusion were discussed and resolved by consensus.

Data Extraction

Data extraction was done independently by 2 authors (J.S. and M.A.I.). From each eligible study, we extracted the following information into a predefined Excel spreadsheet: first author’s last name, study design, country of the participants, data collection period, total number of patients with COVID-19, number of female patients with COVID-19, age, positive RT-PCR for SARS-CoV-2 RNA, subjective or objective test of taste disorders, and taste abilities and types of taste disorder investigated.

Quality Assessment

The quality of included studies was assessed independently by 2 authors (J.S. and M.A.I.) using the Joanna Briggs Institute critical appraisal tools,¹⁴ and all authors took part in the discussion to resolve any discrepancies. The studies were classified as low quality (high risk of bias) if the overall score was ≤50%. To assess publication bias, a funnel plot presenting prevalence estimate against the standard error was constructed, and the asymmetry of the funnel plot was confirmed with Egger’s test.

Data Analyses

A random effects model was used to obtain the pooled prevalence and 95% CIs of taste disorders in patients with COVID-19. Heterogeneity among studies was assessed with the I² statistic (I² >75% indicating substantial heterogeneity) in addition to the Cochran’s Q test to identify the significance of heterogeneity, where P <. 10 was considered statistically significant. Additionally, to identify the outlier studies and the sources of heterogeneity, a Galbraith plot was constructed. All the analyses and plots were generated by using metaprop codes in the meta (version 4.11-0) and metafor (version 2.4-0) packages of R (version 3.6.3) in RStudio (version 1.2.5033).¹⁵

Subgroup and Sensitivity Analyses

For subgroup analysis, the prevalence of taste disorders in patients with COVID-19 was analyzed by geographic region, type of taste disorder (ageusia, hypogeusia, and dysgeusia), and type of assessment (subjective or objective). To identify the source of heterogeneity and to check the robustness of the results, sensitivity analyses were performed through the following strategies: (1) excluding small studies (n < 100), (2) excluding the low-quality studies (high risk of bias), (3) excluding studies not reporting COVID-19 confirmation assay, (4) excluding the outlier studies, and (5) considering only cross-sectional studies.

Results

Study Selection

Our search initially identified 775 studies. After removal of 379 studies (duplicate studies, n = 318; review articles, n = 47; case reports, n = 14), titles and abstracts of 396 studies were screened for eligibility, of which 337 were excluded because of lack of relevant and sufficient data on prevalence. Finally, 59 studies were included in the systematic review and meta-analysis (Figure 1).

Study Characteristics

Detailed characteristics and references of the included studies are presented in Supplemental Table S2 (available online). Overall, this meta-analysis reports data from 29,349 patients with COVID-19 (64.4% female). The ages of these patients ranged from 28.0 ± 16.4 to 66.4 ± 14.9 years (mean ± SD; range, 15.0-93.0). Studies were from 5 continents—Europe (n = 19,496), Asia (n = 5636), North America (n = 1100), South America (n = 148), and Australia (n = 28)—including 23 countries: United Kingdom, Italy, Spain, Poland, Turkey, France, Belgium, Switzerland, Germany, United States, Canada, China, Korea, Iraq, Iran, Israel, Saudi Arabia, Brazil, Argentina, Uruguay, Bolivia, Venezuela, and Australia. Among the included studies, 96.6% of COVID-19 cases were confirmed by reverse transcription polymerase chain reaction (RT-PCR), whereas the method was not reported in 2 studies.

Details are in the caption following the image — **Figure 1**
Open in figure viewer

PRISMA flow diagram of study selection.

Quality Assessment

Detailed quality assessment of the included studies is shown in Supplemental Tables S3 and S4 (available online). Briefly, 91.5% of the included studies were of high quality (low risk of bias). Visual inspection of the funnel plot and Egger’s test results revealed no significant publication bias (P =. 68; Figure 2).

Outcomes

The pooled prevalence of taste disorders in cases of COVID-19 was 48.1% (95% CI, 41.3%-54.8%; Figure 3). From the subgroup analyses, we observed taste disorders in 55.2% of European patients with COVID-19; 61.0%, North American; 27.1%, Asian; 29.5%, South American; and 25.0%, Australian (Table 1; Supplemental Figure S1, available online). Additionally, ageusia, hypogeusia, and dysgeusia were observed in 28.0%, 33.5%, and 41.3% of patients with COVID-19, respectively (Supplemental Figure S2). Interestingly, the prevalence of taste disorders in studies with objective assessment was higher when compared with subjective assessment (59.2% vs 47.3%; Supplemental Figure S3). Overall, very high levels of heterogeneity (range, 71%-99%) were observed during the estimation of taste disorders in the main analysis as well as in subgroup analyses. From the Galbraith plot, 4 studies were identified as the potential sources of heterogeneity (Figure 4).

Sensitivity Analyses

Sensitivity analyses on assessing taste disorders in cases of COVID-19—when excluding small studies, low-quality studies, studies where the COVID-19 confirmation test was not reported, and outlier studies and when considering only cross-sectional studies—showed marginal differences (2.5% lower to 3.8% higher) in pooled prevalence as compared with the main findings (Table 2; Supplemental Figure S4, available online). Our sensitivity analyses indicated that the results are robust and reliable in terms of reporting the prevalence of taste disorders in patients with COVID-19.

Table 1. Pooled Prevalence of Taste Disorders in Subgroups of Patients With COVID-19.^a

Subgroup	Prevalence (95% CI), %	No. of studies	No. of patients with COVID-19	Heterogeneity		Publication bias, P value^b
Subgroup	Prevalence (95% CI), %	No. of studies	No. of patients with COVID-19	I², %	P value	Publication bias, P value^b
Region
Europe	55.2 (47.4-63.0)	37	19,496	99.0	<.001	.19
North America	61.0 (51.9-70.0)	7	1100	82.0	<.001
Asia	27.1 (21.0-33.2)	13	5636	96.0	<.001	.22
South America	29.5 (0.0-89.7)	2	148	81.0	.02
Australia	25.0 (9.0-41.0)	1	28
Type
Ageusia	28.0 (20.2-35.90)	17	8856	99.0	<.001	.004
Hypogeusia	33.5 (24.6-42.4)	8	1366	92.0	<.001
Dysgeusia	41.3 (26.7-55.8)	16	3347	99.0	<.001	.92
Assessment
Subjective	47.3 (40.4-54.3)	55	28,847	99.0	<.001	.72
Objective	59.2 (49.0-69.3)	4	502	71.0	.01

a Blank cells indicate not applicable.
b Egger’s test.

Discussion

New onset of taste disorders has been described as a potential early symptom of COVID-19 infection. It may present with an olfactory dysfunction or as an isolated symptom.⁸^,¹⁶ The oral cavity is one of the possible routes of entry for COVID-19 infection, as corroborated by the discovery of SARS-CoV-2 in saliva and the damage of epithelial cells in the oral cavity among infected patients.^17-19 Gustation is related to sensory input as perceived by the taste receptors following oral intake; these receptors are located mainly in the oral cavity, and any alteration in this setting will cause taste dysfunction.²⁰ There is growing evidence that taste disorders are more frequent than olfactory disturbances, thereby disputing the close correlation between these dysfunctions and creating a new hypothesis of other factors responsible for taste disorders in cases of COVID-19.⁴^,²¹

Table 2. Strategies of Sensitivity Analyses.

Strategy	Prevalence of taste disorders (95% CI), %	Difference of pooled prevalence vs main result, %	No. of studies	No. of patients with COVID-19	Heterogeneity
Strategy	Prevalence of taste disorders (95% CI), %	Difference of pooled prevalence vs main result, %	No. of studies	No. of patients with COVID-19	I², %	P value
Excluding studies that were
Small	46.8 (37.8-55.8)	2.5 lower	33	27,862	100.0	<.0001
Low quality	48.2 (41.2-55.3)	0.4 higher	54	28,993	99.0	<.0001
Lacking COVID-19 confirmation assay	49.2 (42.4-56.0)	2.4 higher	57	29,145	99.0	<.0001
Outliers	49.9 (45.3-54.5)	3.8 higher	53	24,563	98.0	<.0001
Considering only cross-sectional studies	47.9 (40.8-55.0)	0.3 lower	54	28,929	99.0	<.0001

In our meta-analysis, a high prevalence of taste disorders in patients with COVID-19 was noted across all 59 included studies. Underreporting and underestimation may explain the difference in prevalence across the world. There is a tendency for underreporting for patients in the Asia continent, while underestimation may occur from the observational nature of the included studies, such as medical report review. It is interesting to note that the preliminary data from Wuhan, the epicenter of SARS-CoV-2, failed to disclose taste disorders as one of the manifestations of SARS-CoV-2 infection.²²^,²³ There might be fewer such complaints in Chinese patients, or it could have been overlooked, as the assessment was more focused on the critical regions, such as the lower respiratory tract. There are differences between the major types of SARS-CoV-2 (S and L), owing to its single-nucleotide polymorphisms. Early cases in Wuhan revealed the L type of SARS-CoV-2 to be more widespread, which subsequently reduced in numbers.²⁴ Different binding rates of the SARS-CoV-2 glycoprotein, which binds to host cell receptors, account for the various disease manifestations across the population.⁵^,²⁵ Additionally, ACE2 (angiotensin converting enzyme 2), the receptor of SARS-CoV-2, has variable expression levels among different populations.²⁶ This distinction is another possible explanation for the different manifestations across populations worldwide.

There are 3 types of taste disorders observed in our meta-analysis (Table 1). Comparison revealed that dysgeusia has a higher prevalence (41.3%) than ageusia (28.0%) and hypogeusia (33.5%). Although the exact mechanisms underlying the different presentation of taste disorders among patients with COVID-19 infection remain unclear, there are several possible explanations. All 3 types of taste disorder may occur as a result of damage along the central taste pathway, including the brainstem, thalamus, cranial nerves, or cerebral cortex. Earlier evidence showed that cerebral involvement in COVID-19 might ensue during the early and late phases of infection.²⁷ Ageusia (complete loss of taste) and hypogeusia (reduced taste sensation) may occur due to disturbance of the composition and volume of saliva as well as the compromised epithelial cells of the tongue. Dysgeusia, which is a state of altered or distorted taste perception, may arise from isolated injury to any one of the major nerve pathways. Taste perception may also be altered when there is an olfactory dysfunction that affects the central multisensory input, as the overall taste perception is the culmination process of the integrated central multisensory system with the primary taste sensation.²⁸ However, it cannot be excluded that the self-reported questionnaire may be confusing to patients. Rather than evaluating the ability to identify the primary taste, it may instead evaluate the perception of flavor.²⁹

Even though earlier meta-analyses^30-32 acknowledged that dysgeusia is the most common impairment among patients with COVID-19, they did not perform any subgroup analysis for the different types of taste disorders, and this highlights the new contribution of our meta-analysis. Female predominance was noted in our meta-analysis, forming 64.4% of patients. Women are more sensitive to changes in chemosensory dysfunction than their male counterparts, and this sensitivity may explain the differences in their prevalence. Another explanation is the sex differences in inflammatory cytokine production,³³ but more studies are required to prove the causality.

Four objective studies are included in our meta-analysis. Remarkably, all of them showed a higher prevalence rate of taste disorders (59.2%) than the subjective studies (47.3%). Adamczyk et al³⁴ showed that the self-reported questionnaire has a sensitivity of 77% and a specificity of 86% for detecting taste disorders, but when the objective taste test was performed, the sensitivity increases to 94% and the specificity to 100%. In a single-center study in Italy with 72 patients, Vaira et al³⁵ disclosed that the taste test was able to establish 47% of patients with taste disorders. Their results contradict earlier studies on the self-reported questionnaire, which had a lower prevalence rate. A multicenter cohort study evaluating objective chemosensitive dysfunction among 345 patients with COVID-19 found underreporting of chemosensitive disorders in 2 groups of patients—one consisting of patients in home quarantine and the other of patients who were hospitalized.³⁶ As the hospitalized group represents the severe COVID-19 infection, its result refutes the view that the presence of chemosensitive dysfunction signals a mild to moderate infection and construes that those with severe disease tend to neglect such symptoms. The use of the objective taste test revealed that 44.9% of the patients had taste disorders.

To overcome the hurdles of performing an objective taste test—which is a hospital-centric procedure, with its inherent risk of infection transmission to health care providers and other patients—a home-based taste test is suggested as an alternative. Vaira et al³⁷ assessed a home-based objective taste test performed by patients and demonstrated that it was reliable in detecting taste disorders. Of the 33 patients who were quarantined with COVID-19 infection, 51.5% was confirmed to have taste dysfunction. The authors proposed that a home-based objective taste test may form a good public health strategy for early detection of paucisymptomatic COVID-19 cases to break the chain of transmission by isolation of the infected patients.

The results of our meta-analysis are in line with the finding of an earlier meta-analysis by Borsetto et al,³¹ which discovered that subjective assessment with self-reported questionnaires appears to underestimate the prevalence of taste disorders. Interestingly, Hintschich et al³⁸ demonstrated that patients with self-reported taste disorders did not exhibit a genuine impaired taste when confirmed by objective taste test, thereby alluding to impaired retronasal olfaction as the cause of the altered taste. This could be explained by the intimate relationship between olfaction and the perception of flavor, giving rise to the subjective taste disorders.

Underestimation and underreporting of a less critical manifestation are common phenomena in any condition when the focus is more on life-threatening organ damage³⁹; in COVID-19 infection, the focus is on pulmonary failure and death. As taste is 1 of the 5 senses, when it is ignored and the effect of taste disorders on the quality of life of patients is underestimated, it means rendering suboptimal treatment and thus delivering inferior quality of care. Recovery of patients depends not only on the treatment but also on the resumption of an appropriately composed diet, which may assist the body’s innate immunity to fight against infection and the repairing process of damaged cells. Dietary composition and nutrition, especially those known as antioxidants, have been proposed as the determinants behind the variable death rate of different European countries, which highlights their critical roles as a protective mechanism against infection.⁴⁰

Given the significance of taste disorders in COVID-19 infection, further studies employing reliable and vigorous objective testing are required for its evaluation. As explanation is still lacking regarding the reasons why certain groups of patients presented with either taste dysfunction or olfactory dysfunction (or both), a much-needed clarification may emanate from a neurologic assessment of the neural pathways involved. It is acknowledged that the interaction between host and virus characteristics is responsible, but further investigations are required.

Strengths and Limitations

Our study has several strengths. This meta-analysis is the first, to our knowledge, to comprehensively investigate the prevalence of taste disorders in patients with COVID-19. This meta-analysis was conducted with a substantial number of studies^{3, 4, 8-10, 12, 19, 21, 34-37, 41-87} and hence included a considerable number of participants, resulting in more robust estimates. The majority of the included studies confirmed COVID-19 cases with the RT-PCR technique, which strengthens our findings. None of the analyses represented significant publication bias, demonstrating that we were unlikely to have missed studies that could have altered the findings. All the conducted sensitivity analyses generated very similar results to the main findings, indicating the robustness of the meta-analysis results. Based on the quality assessments, 91.5% of the studies were of high methodological quality (low risk of bias), which ensured a reliable result.

Nevertheless, there are several notable limitations. Based on the search strategy and considered period, this meta-analysis included participants from 23 countries; therefore, the prevalence may not represent a global scale, and generalization of the findings should be done cautiously. All analyses demonstrated substantial degrees of heterogeneity. Even though we examined the sources of heterogeneity by subgroup, sensitivity analyses, and Galbraith plot, the source of heterogeneity could not be fully explained by the factors included in the analyses. While we identified the prevalence of taste disorders, we were unable to characterize them in severe versus nonsevere COVID-19 infection and in cases of survival versus nonsurvival.

Conclusions

As an early clinical symptom in patients with COVID-19, taste disorder had a prevalence of 48.1%. Objective assessments tend to show higher prevalence than subjective assessments. Dysgeusia is the most common subtype, followed by ageusia and hypogeusia. Due to the high prevalence of taste disorders in cases of COVID-19, proper screening and evaluation should be performed.

Author Contributions

Jeyasakthy Saniasiaya, concept/design, data analysis, drafting and editing of manuscript, final approval, accountability; Md Asiful Islam, concept/design, data analysis, drafting and editing of manuscript, final approval, accountability; Baharudin Abdullah, concept/design, data analysis, drafting and editing of manuscript, final approval, accountability.

Disclosures

Competing interests: None.

Sponsorships: None.

Funding source: None.

Supplemental Material

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References

*Asterisks indicate studies included in meta-analysis. For details, see Supplemental Table S2.

1 World Health Organization. Coronavirus disease 2019 (COVID-19) situation report—209. Published August 16, 2020. Accessed August 18, 2020. https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports

Google Scholar
2 Centers for Disease Control and Prevention. Symptoms of coronavirus. Accessed May 30, 2020. https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html

Google Scholar
3Mao L, Jin H, Wang M, et al. Neurologic manifestations of hospitalized patients with coronavirus disease 2019 in Wuhan, China. JAMA Neurol. Published online June 1, 2020. doi:2010.1001/jamaneurol.2020.1127
10.1001/jamaneurol.2020.1127
Web of Science®Google Scholar
4Lechien JR, Chiesa-Estomba CM, De Siati DR, et al. Olfactory and gustatory dysfunctions as a clinical presentation of mild-to-moderate forms of the coronavirus disease (COVID-19): a multicenter European study. Eur Arch Otorhinolaryngol. Published online April 6, 2020. doi:2010.1007/s00405-00020-05965-00401
10.1007/s00405-020-05965-1
Web of Science®Google Scholar
5Benvenuto D, Giovanetti M, Ciccozzi A, Spoto S, Angeletti S, Ciccozzi M. The 2019-new coronavirus epidemic: evidence for virus evolution. J Med Virol. 2020; 92: 455–459.
10.1002/jmv.25688
CASPubMedWeb of Science®Google Scholar
6Chan JF-W, Yuan S, Kok K-H, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020; 395: 514–523.
10.1016/S0140-6736(20)30154-9
CASPubMedWeb of Science®Google Scholar
7Aziz M, Perisetti A, Lee-Smith WM, Gajendran M, Bansal P, Goyal H. Taste changes (dysgeusia) in COVID-19: a systematic review and metaanalysis. Gastroenterology. Published online April 15, 2020. doi:2010.1053/j.gastro.2020.2005.2003
10.1053/j.gastro.2020.05.003
Web of Science®Google Scholar
8Beltrán-Corbellini Á, Chico-García JL, Martínez-Poles J, et al. Acute-onset smell and taste disorders in the context of COVID-19: a pilot multicenter PCR-based case-control study. Eur J Neurol. Published online April 22, 2020. doi:2010.1111/ene.14273
10.1111/ene.14273
PubMedWeb of Science®Google Scholar
9Dawson P, Rabold EM, Laws RL, et al. Loss of taste and smell as distinguishing symptoms of COVID-19. medRxiv. Published online June 21, 2020. doi:2010.1101/2020.2005.2013.20101006

Google Scholar
10De Maria A, Varese P, Dentone C, Barisione E, Bassetti M. High prevalence of olfactory and taste disorder during SARS-CoV-2 infection in outpatients. J Med Virol. Published online May 8, 2020. doi:2010.1002/jmv.25995
10.1002/jmv.25995
PubMedWeb of Science®Google Scholar
11Whitcroft KL, Hummel T. Olfactory dysfunction in COVID-19: diagnosis and management. JAMA. Published online May 20, 2020. doi:2010.1001/jama.2020.8391
10.1001/jama.2020.8391
PubMedWeb of Science®Google Scholar
12Lechien JR, Cabaraux P, Chiesa-Estomba CM, et al. Objective olfactory evaluation of self-reported loss of smell in a case series of 86 COVID-19 patients. Head Neck. Published online May 21, 2020. doi:2010.1002/hed.26279
10.1002/hed.26279
Web of Science®Google Scholar
13Moher D, Liberati A, Tetzlaff J, Altman DG; PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009; 6: 1–6.
10.1371/journal.pmed.1000097
Web of Science®Google Scholar
14 Joanna Briggs Institute. Critical Appraisal Tools. The University of Adelaide; 2018. https://joannabriggs.org/ebp/critical_appraisal_tools

Google Scholar
15Viechtbauer W. Conducting meta-analyses in R with the metafor package. J Stat Softw. 2010; 36: 1–48.
10.18637/jss.v036.i03
Web of Science®Google Scholar
16Roland LT, Gurrola JG, Loftus PA, Cheung SW, Chang JL. Smell and taste symptom-based predictive model for COVID-19 diagnosis. Int Forum Allergy Rhinol. Published online May 4, 2020. doi:2010.1002/alr.22602
10.1002/alr.22602
Web of Science®Google Scholar
17Xu H, Zhong L, Deng J, et al. High expression of ACE2 receptor of 2019-nCoV on the epithelial cells of oral mucosa. Int J Oral Sci. 2020; 12: 1–5.
10.1038/s41368-020-0074-x
PubMedWeb of Science®Google Scholar
18To KK-W, Tsang OT-Y, Leung W-S, et al. Temporal profiles of viral load in posterior oropharyngeal saliva samples and serum antibody responses during infection by SARS-CoV-2: an observational cohort study. Lancet Infect Dis. 2020; 20: 565–574.
10.1016/S1473-3099(20)30196-1
CASPubMedWeb of Science®Google Scholar
19Lee Y, Min P, Lee S, Kim SW. Prevalence and duration of acute loss of smell or taste in COVID-19 patients. J Korean Med Sci. 2020; 35: 1–6.

Web of Science®Google Scholar
20Hunt JD, Reiter ER, Costanzo RM. Etiology of subjective taste loss. Int Forum Allergy Rhinol. 2019; 9: 409–412.
10.1002/alr.22263
PubMedWeb of Science®Google Scholar
21Yan CH, Faraji F, Prajapati DP, Boone CE, DeConde AS. Association of chemosensory dysfunction and COVID-19 in patients presenting with influenza-like symptoms. Int Forum Allergy Rhinol. Published online April 12, 2020. doi:2010.1002/alr.22579
10.1002/alr.22579
Web of Science®Google Scholar
22Chen N, Zhou M, Dong X, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020; 395: 507–513.
10.1016/S0140-6736(20)30211-7
CASPubMedWeb of Science®Google Scholar
23Guan W-J, Ni Z-Y, Hu Y, et al. Clinical characteristics of coronavirus disease 2019 in China. N Engl J Med. 2020; 382: 1708–1720.
10.1056/NEJMoa2002032
CASPubMedWeb of Science®Google Scholar
24Tang X, Wu C, Li X, et al. On the origin and continuing evolution of SARS-CoV-2. Natl Sci Rev. Published online March 3, 2020. doi:2010.1093/nsr/nwaa2036
10.1093/nsr/nwaa036
PubMedWeb of Science®Google Scholar
25Phan T. Genetic diversity and evolution of SARS-CoV-2. Infect Genet Evol. 2020; 81: 104260.
10.1016/j.meegid.2020.104260
CASPubMedWeb of Science®Google Scholar
26Li W, Zhang C, Sui J, et al. Receptor and viral determinants of SARS-coronavirus adaptation to human ACE2. EMBO J. 2005; 24: 1634–1643.
10.1038/sj.emboj.7600640
CASPubMedWeb of Science®Google Scholar
27Netland J, Meyerholz DK, Moore S, Cassell M, Perlman S. Severe acute respiratory syndrome coronavirus infection causes neuronal death in the absence of encephalitis in mice transgenic for human ACE2. J Virol. 2008; 82: 7264–7275.
10.1128/JVI.00737-08
CASPubMedWeb of Science®Google Scholar
28Maier JX, Blankenship ML, Li JX, Katz DB. A multisensory network for olfactory processing. Curr Biol. 2015; 25: 2642–2650.
10.1016/j.cub.2015.08.060
CASPubMedWeb of Science®Google Scholar
29Stevenson RJ, Prescott J, Boakes RA. Confusing tastes and smells: how odours can influence the perception of sweet and sour tastes. Chem Senses. 1999; 24: 627–635.
10.1093/chemse/24.6.627
CASPubMedWeb of Science®Google Scholar
30Tong JY, Wong A, Zhu D, Fastenberg JH, Tham T. The prevalence of olfactory and gustatory dysfunction in COVID-19 patients: a systematic review and meta-analysis. Otolaryngol Head Neck Surg. 2020; 163: 3–11.
10.1177/0194599820926473
PubMedWeb of Science®Google Scholar
31Borsetto D, Hopkins C, Philips V, et al. Self-reported alteration of sense of smell or taste in patients with COVID-19: a systematic review and meta-analysis on 3563 patients. Rhinology. Published online October 1, 2020. doi:2010.4193/Rhin2020.2185
10.4193/Rhin20.185
Web of Science®Google Scholar
32Hoang MP, Kanjanaumporn J, Aeumjaturapat S, Chusakul S, Seresirikachorn K, Snidvongs K. Olfactory and gustatory dysfunctions in COVID-19 patients: a systematic review and meta-analysis. Asian Pac J Allergy Immunol. Published online September 25, 2020. doi:2010.12932/AP-210520-210853

PubMedWeb of Science®Google Scholar
33Lefèvre N, Corazza F, Valsamis J, et al. The number of X chromosomes influences inflammatory cytokine production following toll-like receptor stimulation. Front Immunol. 2019; 10: 1–11.
10.3389/fimmu.2019.01052
PubMedWeb of Science®Google Scholar
34Adamczyk K, Herman M, Fraczek J, et al. Sensitivity and specifity of prediction models based on gustatory disorders in diagnosing COVID-19 patients: a case-control study. medRxiv. Published online June 3, 2020. doi:2010.1101/2020.2005.2031.20118380

Google Scholar
35Vaira LA, Deiana G, Fois AG, et al. Objective evaluation of anosmia and ageusia in COVID-19 patients: single-center experience on 72 cases. Head Neck. Published online April 27, 2020. doi:2010.1002/hed.26204
10.1002/hed.26204
Web of Science®Google Scholar
36Vaira A, Hopkins C, Salzano G, et al. Olfactory and gustatory function impairment in COVID-19 patients: Italian objective multicenter-study. Head Neck. Published online May 21, 2020. doi:2010.1002/hed.26269
10.1002/hed.26269
Web of Science®Google Scholar
37Vaira LA, Salzano G, Petrocelli M, Deiana G, Salzano FA, De Riu G. Validation of a self-administered olfactory and gustatory test for the remotely evaluation of COVID-19 patients in home quarantine. Head Neck. Published online May 1, 2020. doi:2010.1002/hed.26228
10.1002/hed.26228
Web of Science®Google Scholar
38Hintschich CA, Wenzel JJ, Hummel T, et al. Psychophysical tests reveal impaired olfaction but preserved gustation in COVID-19 patients. Int Forum Allergy Rhinol. Published online July 1, 2020. doi:2010.1002/alr.22655
10.1002/alr.22655
PubMedWeb of Science®Google Scholar
39Gibbons CL, Mangen M-JJ, Plass D, et al. Measuring underreporting and under-ascertainment in infectious disease datasets: a comparison of methods. BMC Public Health. 2014; 14: 1–17.
10.1186/1471-2458-14-147
PubMedWeb of Science®Google Scholar
40Bousquet J, Anto JM, Iaccarino G, et al. Is diet partly responsible for differences in COVID-19 death rates between and within countries? Clin Transl Allergy. 2020; 10: 1–7.

PubMedWeb of Science®Google Scholar
41Abalo-Lojo JM, Pouso-Diz JM, Gonzalez F. Taste and smell dysfunction in COVID-19 patients. Ann Otol Rhinol Laryngol. Published online May 29, 2020. doi:2010.1177/0003489420932617
10.1177/0003489420932617
PubMedWeb of Science®Google Scholar
42Aggarwal S, Garcia-Telles N, Aggarwal G, Lavie C, Lippi G, Henry BM. Clinical features, laboratory characteristics, and outcomes of patients hospitalized with coronavirus disease 2019 (COVID-19): early report from the United States. Diagnosis. 2020; 7: 91–96.
10.1515/dx-2020-0046
CASPubMedWeb of Science®Google Scholar
43Alshami AA, Alattas RA, Anan HF, et al. Silent disease and loss of taste and smell are common manifestations of SARS-COV-2 infection in a quarantine facility: first report from Saudi Arabia. medRxiv. Published online February 22, 2020. doi:2010.1101/2020.2005.2013.20100222

Google Scholar
44Biadsee A, Biadsee A, Kassem F, Dagan O, Masarwa S, Ormianer Z. Olfactory and oral manifestations of COVID-19: sex-related symptoms—a potential pathway to early diagnosis. Otolaryngol Head Neck Surg. Published online June 16, 2020. doi:2010.1177/0194599820934380
10.1177/0194599820934380
PubMedWeb of Science®Google Scholar
45Carignan A, Valiquette L, Grenier C, et al. Anosmia and dysgeusia associated with SARS-CoV-2 infection: an age-matched case-control study. Can Med Assoc J. Published online June 29, 2020. doi:2010.1503/cmaj.200869
10.1503/cmaj.200869
Web of Science®Google Scholar
46Chary E, Carsuzaa F, Trijolet J-P, et al. Prevalence and recovery from olfactory and gustatory dysfunctions in COVID-19 infection: a prospective multicenter study. Am J Rhinol Allergy. Published online June 12, 2020. doi:2010.1177/1945892420930954
10.1177/1945892420930954
PubMedWeb of Science®Google Scholar
47Chiesa-Estomba CM, Lechien JR, Portillo-Mazal P, et al. Olfactory and gustatory dysfunctions in COVID-19: first reports of Latin-American ethnic patients. Am J Otolaryngol. 2020; 41: 1–2.
10.1016/j.amjoto.2020.102605
Web of Science®Google Scholar
48Dell’Era V, Farri F, Garzaro G, Gatto M, Aluffi Valletti P, Garzaro M. Smell and taste disorders during COVID-19 outbreak: a cross-sectional study on 355 patients. Head Neck. Published online June 11, 2020. doi:2010.1002/hed.26288
10.1002/hed.26288
PubMedWeb of Science®Google Scholar
49Gelardi M, Trecca E, Cassano M, Ciprandi G. Smell and taste dysfunction during the COVID-19 outbreak: a preliminary report. Acta Biomed. 2020; 91: 230–231.

CASPubMedGoogle Scholar
50Giacomelli A, Pezzati L, Conti F, et al. Self-reported olfactory and taste disorders in patients with severe acute respiratory coronavirus 2 infection: a cross-sectional study. Clin Infect Dis. Published online July 28, 2020. doi:2010.1093/cid/ciaa2330
10.1093/cid/ciaa330
Web of Science®Google Scholar
51Izquierdo-Domínguez A, Rojas-Lechuga M, Chiesa-Estomba C, et al. Smell and taste dysfunctions in COVID-19 are associated with younger age in ambulatory settings—a multicenter cross-sectional study. J Investig Allergol Clin Immunol. Published online June 17, 2020. doi:2010.18176/jiaci.10595
10.18176/jiaci.0595
Web of Science®Google Scholar
52Kim GU, Kim MJ, Ra SH, et al. Clinical characteristics of asymptomatic and symptomatic patients with mild COVID-19. Clin Microbiol Infect. Published online May 1, 2020. doi:2010.1016/j.cmi.2020.2004.2040
10.1016/j.cmi.2020.04.040
Web of Science®Google Scholar
53Klopfenstein T, Kadiane-Oussou NJ, Toko L, et al. Features of anosmia in COVID-19. Med Mal Infect. Published online April 17, 2020. doi:2010.1016/j.medmal.2020.2004.2006
10.1016/j.medmal.2020.04.006
Web of Science®Google Scholar
54Kosugi EM, Lavinsky J, Romano FR, et al. Incomplete and late recovery of sudden olfactory dysfunction in COVID-19. Braz J Otorhinolaryngol. Published online May 25, 2020. doi:2010.1016/j.bjorl.2020.2005.2001
10.1016/j.bjorl.2020.05.001
Web of Science®Google Scholar
55Lagi F, Piccica M, Graziani L, et al. Early experience of an infectious and tropical diseases unit during the coronavirus disease (COVID-19) pandemic, Florence, Italy, February to March 2020. Eurosurveillance. 2020; 25: 1–6.
10.2807/1560-7917.ES.2020.25.17.2000556
CASWeb of Science®Google Scholar
56Lapostolle F, Schneider E, Vianu I, et al. Clinical features of 1487 COVID-19 patients with outpatient management in the Greater Paris: the COVID-call study. Intern Emerg Med. Published online May 30, 2020. doi:2010.1007/s11739-11020-02379-z
10.1007/s11739-020-02379-z
PubMedWeb of Science®Google Scholar
57Lechien JR, Chiesa-Estomba CM, Place S, et al. Clinical and epidemiological characteristics of 1,420 European patients with mild-to-moderate coronavirus disease 2019. J Intern Med. Published online June 17, 2020. doi:2010.1111/joim.13089
10.1111/joim.13089
PubMedWeb of Science®Google Scholar
58Lechien JR, Chiesa-Estomba CM, Hans S, Barillari MR, Jouffe L, Saussez S. Loss of smell and taste in 2013 European patients with mild to moderate COVID-19. Ann Intern Med. Published online May 26, 2020. doi:2010.7326/M2020-2428
10.7326/M20-2428
PubMedWeb of Science®Google Scholar
59Lee DJ, Lockwood J, Das P, Wang R, Grinspun E, Lee JM. Self-reported anosmia and dysgeusia as key symptoms of COVID-19. CJEM. Published online June 8, 2020. doi:2010.1017/cem.2020.2420

Google Scholar
60Levinson R, Elbaz M, Ben-Ami R, et al. Anosmia and dysgeusia in patients with mild SARS-CoV-2 infection. medRxiv. Published online April 14, 2020. doi:2010.1101/2020.2004.2011.20055483

PubMedGoogle Scholar
61Liguori C, Pierantozzi M, Spanetta M, et al. Subjective neurological symptoms frequently occur in patients with SARS-CoV2 infection. Brain Behav Immun. Published online May 19, 2020. doi:2010.1016/j.bbi.2020.2005.2037
10.1016/j.bbi.2020.05.037
PubMedWeb of Science®Google Scholar
62Luers JC, Rokohl AC, Loreck N, et al. Olfactory and gustatory dysfunction in coronavirus disease 19 (COVID-19). Clin Infect Dis. Published online May 1, 2020. doi:2010.1093/cid/ciaa2525
10.1093/cid/ciaa525
Web of Science®Google Scholar
63Meini S, Suardi LR, Busoni M, Roberts AT, Fortini A. Olfactory and gustatory dysfunctions in 100 patients hospitalized for COVID-19: sex differences and recovery time in real-life. Eur Arch Otorhinolaryngol. Published online May 29, 2020. doi:2010.1007/s00405-00020-06102-00408
10.1007/s00405-020-06102-8
PubMedWeb of Science®Google Scholar
64Menni C, Valdes A, Freydin MB, et al. Loss of smell and taste in combination with other symptoms is a strong predictor of COVID-19 infection. medRxiv. Published online April 7, 2020. doi:2010.1101/2020.2004.2005.20048421

Google Scholar
65Menni C, Valdes AM, Freidin MB, et al. Real-time tracking of self-reported symptoms to predict potential COVID-19. Nat Med. Published online May 11, 2020. doi:2010.1038/s41591-41020-40916-41592
10.1038/s41591-020-0916-2
PubMedWeb of Science®Google Scholar
66Mercante G, Ferreli F, De Virgilio A, et al. Prevalence of taste and smell dysfunction in coronavirus disease 2019. JAMA Otolaryngol Head Neck Surg. Published online June 18, 2020. doi:2010.1001/jamaoto.2020.1155
10.1001/jamaoto.2020.1155
PubMedWeb of Science®Google Scholar
67Merza MA, Haleem Al, Mezori AA, Mohammed HM, Abdulah DM. COVID-19 outbreak in Iraqi Kurdistan: the first report characterizing epidemiological, clinical, laboratory, and radiological findings of the disease. Diabetes Metab Syndr. 2020; 14: 547–554.
10.1016/j.dsx.2020.04.047
PubMedWeb of Science®Google Scholar
68Moein ST, Hashemian SMR, Mansourafshar B, Khorram-Tousi A, Tabarsi P, Doty RL. Smell dysfunction: a biomarker for COVID-19. Int Forum Allergy Rhinol. Published online April 17, 2020. doi:2010.1002/alr.22587
10.1002/alr.22587
PubMedWeb of Science®Google Scholar
69Moro E, Priori A, Beghi E, et al. The international EAN survey on neurological symptoms in patients with COVID-19 infection. Eur J Neurol. Published online June 17, 2020. doi:2010.1111/ene.14407
10.1111/ene.14407
Web of Science®Google Scholar
70Noh JY, Yoon JG, Seong H, et al. Asymptomatic infection and atypical manifestations of COVID-19: comparison of viral shedding duration. J Infect. Published online May 21, 2020. doi:2010.1016/j.jinf.2020.2005.2035
10.1016/j.jinf.2020.05.035
PubMedWeb of Science®Google Scholar
71Paderno A, Schreiber A, Grammatica A, et al. Smell and taste alterations in COVID-19: a cross-sectional analysis of different cohorts. Int Forum Allergy Rhinol. Published online May 14, 2020. doi:2010.1002/alr.22610
10.1002/alr.22610
PubMedWeb of Science®Google Scholar
72Patel A, Charani E, Ariyanayagam D, et al. New onset anosmia and ageusia in adult patients diagnosed with SARS-CoV-2 in a London community and secondary care population. SSRN. Published online June 2, 2020. doi:2010.2139/ssrn.3578759

Google Scholar
73Qiu C, Cui C, Hautefort C, et al. Olfactory and gustatory dysfunction as an early identifier of COVID-19 in adults and children: an international multicenter study. medRxiv. Published online June 16, 2020. doi:2010.1101/2020.2005.2013.20100198

Google Scholar
74Renaud M, Leon A, Trau G, et al. Acute smell and taste loss in outpatients: all infected with SARS-CoV-2? Rhinology. Published online August 1, 2020. doi:2010.4193/rhin2020.2199
10.4193/Rhin20.199
PubMedWeb of Science®Google Scholar
75Romero-Sánchez CM, Díaz-Maroto I, Fernández-Díaz E, et al. Neurologic manifestations in hospitalized patients with COVID-19: the ALBACOVID registry. Neurology. Published online August 25, 2020. doi:2010.1212/WNL.0000000000009937
10.1212/WNL.0000000000009937
PubMedWeb of Science®Google Scholar
76Sayin İ, Yaşar KK, Yazici ZM. Taste and smell impairment in COVID-19: an AAO-HNS anosmia reporting tool-based comparative study. Otolaryngol Head Neck Surg. Published online June 9, 2020. doi:2010.1177/0194599820931820
10.1177/0194599820931820
PubMedWeb of Science®Google Scholar
77Schmithausen RM, Döhla M, Schößler H, et al. Characteristic temporary loss of taste and olfactory senses in SARS-CoV-2-positive-individuals with mild symptoms. Pathog Immun. 2020; 5: 117–120.
10.20411/pai.v5i1.374
PubMedGoogle Scholar
78Sierpiński R, Pinkas J, Jankowski M, et al. Gender differences in the frequency of gastrointestinal symptoms and olfactory or taste disorders among 1,942 non-hospitalized patients with COVID-19. Pol Arch Intern Med. Published online June 2, 2020. doi:2010.20452/pamw.15414

Web of Science®Google Scholar
79Song J, Deng Y-K, Wang H, et al. Self-reported taste and smell disorders in patients with COVID-19: distinct features in China. medRxiv. Published online June 15, 2020. doi:2010.1101/2020.2006.2012.20128298

Google Scholar
80Speth MM, Singer-Cornelius T, Obere M, Gengler I, Brockmeier SJ, Sedaghat AR. Olfactory dysfunction and sinonasal symptomatology in COVID-19: prevalence, severity, timing, and associated characteristics. Otolaryngol Head Neck Surg. Published online May 19, 2020. doi:2010.1177/0194599820929185
10.1177/0194599820929185
Web of Science®Google Scholar
81Trubiano JA, Vogrin S, Kwong JC, Holmes NE. Alterations in smell or taste—classic COVID-19? Clin Infect Dis. Published online May 28, 2020. doi:2010.1093/cid/ciaa2655
10.1093/cid/ciaa655
PubMedWeb of Science®Google Scholar
82Tudrej B, Sebo P, Lourdaux J, et al. Self-reported loss of smell and taste in SARS-CoV-2 patients: primary care data to guide future early detection strategies. Research Square. Published online June 9, 2020. doi:2010.21203/rs.21203.rs-28701/v21201

Google Scholar
83Vargas-Gandica J, Winter D, Schnippe R, et al. Ageusia and anosmia, a common sign of COVID-19? A case series from four countries. Preprints. Published online July 14, 2020. doi:2010.20944/preprints202005.200327.v202001.

Google Scholar
84Yan CH, Faraji F, Prajapati DP, Ostrander BT, DeConde AS. Self-reported olfactory loss associates with outpatient clinical course in COVID-19. Int Forum Allergy Rhinol. Published online April 24, 2020. doi:2010.1002/alr.22592
10.1002/alr.22592
Web of Science®Google Scholar
85Zayet S, Klopfenstein T, Mercier J, et al. Contribution of anosmia and dysgeusia for diagnostic of COVID-19 in outpatients. Infection. Published online May 7, 2020. doi:2010.1007/s15010-15020-01442-15013

PubMedWeb of Science®Google Scholar
86Zayet S, Lepiller Q, Zahra H, et al. Clinical features of COVID-19 and influenza: a comparative study on Nord Franche-Comte cluster. Microbes Infect. Published online June 16, 2020. doi:2010.1016/j.micinf.2020.2005.2016
10.1016/j.micinf.2020.05.016
Web of Science®Google Scholar
87Zou L, Yu T, Zhang Y, Dai L, Zhang Z, Zhang Z. Olfactory and gustatory dysfunctions in patients with COVID-19 in Wuhan, China. Research Square. Published online September 17, 2020. doi:2010.21203/rs.21203.rs-28370/v21201

Google Scholar

Citing Literature

Volume165, Issue1

July 2021

Pages 33-42

Prevalence and Characteristics of Taste Disorders in Cases of COVID-19: A Meta-analysis of 29,349 Patients