Prevalence of Taste and Smell Dysfunction in Coronavirus Disease 2019

COVID-19: immunopathology, pathophysiological mechanisms, and treatment options

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread globally despite the worldwide implementation of preventive measures to combat the disease. Although most COVID-19 cases are characterised by a mild, self-limiting disease course, a considerable subset of patients develop a more severe condition, varying from pneumonia and acute respiratory distress syndrome (ARDS) to multi-organ failure (MOF). Progression of COVID-19 is thought to occur as a result of a complex interplay between multiple pathophysiological mechanisms, all of which may orchestrate SARS-CoV-2 infection and contribute to organ-specific tissue damage. In this respect, dissecting currently available knowledge of COVID-19 immunopathogenesis is crucially important, not only to improve our understanding of its pathophysiology but also to fuel the rationale of both novel and repurposed treatment modalities. Various immune-mediated pathways during SARS-CoV-2 infection are relevant in this context, which relate to innate immunity, adaptive immunity, and autoimmunity. Pathological findings in tissue specimens of patients with COVID-19 provide valuable information with regard to our understanding of pathophysiology as well as the development of evidence-based treatment regimens. This review provides an updated overview of the main pathological changes observed in COVID-19 within the most commonly affected organ systems, with special emphasis on immunopathology. Current management strategies for COVID-19 include supportive care and the use of repurposed or symptomatic drugs, such as dexamethasone, remdesivir, and anticoagulants. Ultimately, prevention is key to combat COVID-19, and this requires appropriate measures to attenuate its spread and, above all, the development and implementation of effective vaccines. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Acute Loss of Smell or Taste Without Nasal Blockage Should Raise Suspicion for COVID-19 Infection

Article Title and Bibliographic Information

Taste and smell as chemosensory dysfunctions in COVID-19 infection. Passarelli PC, Lopez MA, Mastandrea Bonaviri GN, Garcia-Godoy F, D'Addona A.Am J Dent 2020;33(3):135-137.

Source of Funding

Information not available.

Type of Study/Design

Systematic review.

Investigation on the Loss of Taste and Smell and Consequent Psychological Effects: A Cross-Sectional Study on Healthcare Workers Who Contracted the COVID-19 Infection

The aim of this study was to investigate the correlation between psychological distress and taste and sense of smell dysfunctions on healthcare workers (HCW) who contracted the COVID-19 infection in the midst of the disease outbreak. Reports of sudden loss of taste and smell which persist even after recovery from COVID-19 infection are increasingly recognized as critical symptoms for COVID-19 infections. Therefore, we conducted a cross-sectional study on COVID-19 HCW (N = 104) who adhered to respond to a phone semistructured interview addressing the virus symptoms and associated psychological distress. Data were collected from June to September 2020. Findings confirm the association between experienced taste/olfactory loss and emotional distress and suggest that dysfunctions of taste and smell correlate positively with anxiety and depression. Furthermore, their psychological impact tends to persist even after the recovery from the disease, suggesting the need for appropriate psychological interventions to prevent people from developing more serious or long-lasting psychological disorders and, as far as HCW, to reduce the risk of work-related distress.

Prevalence of Anosmia or Ageusia in Patients With COVID-19 Among United Arab Emirates Population

Objective

The aim of this research was to determine the relationship and prevalence of taste and smell dysfunction in patients with COVID-19 in the United Arab Emirates (UAE) population.

Methods

Enrolled participants were interviewed online via a phone call after obtaining their informed consent. Quantification of smell, taste, and other sensations before, during, and after COVID-19 infection was correlated with the severity of COVID-19 symptoms.

Results

A total of 500 patients with (mild–severe) COVID-19 completed the survey. A total of 26.4% were asymptomatic, and 21.4% were classified as paucisymptomatic with less severe symptoms. Almost equal proportions of the studied population experienced extreme taste sensation reductions (43%) and loss of smell sensation (44%). Statistically significant drastic decreases in smell and taste senses were seen among younger individuals. The magnitude of reduction in both sense changes increased steeply from the asymptomatic group to the paucisymptomatic group to the symptomatic group.

Conclusions

Sudden anosmia or ageusia need to be recognised for early detection of COVID-19 infection to identify otherwise hidden carriers, thus favoring an early isolation strategy that will restrict the spread of the disease.

Care of the postcoronavirus disease 2019 patient

PURPOSE OF REVIEW

In under a year, coronavirus disease 2019 (COVID-19) has taken the lives of hundreds of thousands of Americans, leaving millions of survivors in its wake. The enormous number of people who survived acute illness but continue to have symptoms has highlighted the need for standardized evaluation of the post-COVID-19 patient. This review, based on the current literature and our experience, aims to guide the care of patients who have survived COVID-19.

RECENT FINDINGS

The literature on this topic is rapidly expanding and covers both pulmonary and nonpulmonary complications of COVID-19. Pulmonary complications include dyspnea with normoxia, organizing pneumonia and pulmonary fibrosis. Nonpulmonary complications include neurologic, cardiac, and thromboembolic disease. Special consideration should be taken for COVID-19 survivors of intensive care.

SUMMARY

The current review outlines the major clinical findings in post-COVID-19 patients and provides a guidelines to the evaluation and management of prolonged symptoms.

COVID-19-Induced Anosmia and Ageusia Are Associated With Younger Age and Lower Blood Eosinophil Counts

BACKGROUND

Anosmia and ageusia are symptoms commonly associated with COVID-19, but the relationship with disease severity, onset and recovery are unclear.

OBJECTIVE

To examine factors associated with anosmia and ageusia and the recovery from these symptoms in an ethnically diverse cohort.

METHODS

Individuals tested for SARS-CoV-2 between March and April 2020 were eligible for the study. Randomly selected participants answered a telephone questionnaire on COVID-19 symptoms with a focus on anosmia and ageusia. Additionally, relevant past medical history and data on the COVID-19 clinical course were obtained from electronic medical records. 486 patients were in the COVID-19 group and 103 were COVID-19-negative.

RESULTS

Patients who were younger were more likely to report anosmia and/or ageusia (odds ratio (OR) for anosmia per 1-year increase in age: 0·98, 95%CI:0-97-0·99, p = 0·003; for ageusia: 0·98, 95%CI:0·97-0·99, p = 0·005) as were patients with lower eosinophil counts (OR for anosmia per 0.1-K/μL increase in eosinophils: 0·02, 95%CI:0·001-0·46, p = 0·01, for ageusia 0·10, 95%CI:0·01-0·97, p = 0·047). Male gender was independently associated with a lower probability of ageusia (OR:0·56, 95%CI:0·38-0·82, p = 0·003) and earlier sense of taste recovery (HR:1·44, 95%CI:1·05-1·98, p = 0·02). Latinos showed earlier sense of taste recovery than white patients (HR:1·82, 95%CI:1·05-3·18, p = 0·03).

CONCLUSION

Anosmia and ageusia were more common among younger patients and those with lower blood eosinophil counts. Ageusia was less commonly reported among men, and time to taste recovery was earlier among both men and Latinos.

Prevalence of Olfactory Dysfunction in Coronavirus Disease 2019 (COVID-19): A Meta-analysis of 27,492 Patients

OBJECTIVES/HYPOTHESIS

Olfactory dysfunction has been observed as one of the clinical manifestations in COVID-19 patients. We aimed to conduct a systematic review and meta-analysis to estimate the overall pooled prevalence of olfactory dysfunction in COVID-19 patients.

STUDY DESIGN

Systematic review and meta-analyses.

METHODS

PubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between 1 December 2019 and 23 July 2020. We used random-effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I2 statistic and Cochran's Q test. Robustness of the pooled estimates was checked by different subgroup and sensitivity analyses This study is registered with PROSPERO (CRD42020183768).

RESULTS

We identified 1162 studies, of which 83 studies (n = 27492, 61.4% female) were included in the meta-analysis. Overall, the pooled prevalence of olfactory dysfunction in COVID-19 patients was 47.85% [95% CI: 41.20-54.50]. We observed olfactory dysfunction in 54.40% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID-19 patients. Anosmia, hyposmia, and dysosmia were observed in 35.39%, 36.15%, and 2.53% of the patients, respectively. There were discrepancies in the results of studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations. The discrepancy might be due to false-negative reporting observed in self-reported health measures.

CONCLUSIONS

The prevalence of olfactory dysfunction in COVID-19 patients was found to be 47.85% based on high-quality evidence. Due to the subjective measures of most studies pooled in the analysis, further studies with objective measures are advocated to confirm the finding.

LEVEL OF EVIDENCE

2 Laryngoscope, 131:865-878, 2021.

Risk Factors for Olfactory and Gustatory Dysfunctions in Patients with SARS-CoV-2 Infection

INTRODUCTION

Smell and taste loss are characteristic symptoms of SARS-CoV-2 infection. The aim of this study is to investigate the prevalence and risk factors associated with olfactory and gustatory dysfunctions in coronavirus disease (COVID-19) patients.

METHODS

We conducted an observational, retrospective study on 376 patients with documented SARS-CoV-2 infection admitted to the San Gerardo Hospital in Monza, Italy, from March to July 2020. All patients answered a phone questionnaire providing information on age, sex, smoking status, and clinical characteristics. Adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated through logistic regression models including relevant covariates.

RESULTS

The prevalence of olfactory and gustatory dysfunctions in COVID-19 patients was 33.5 and 35.6%, respectively. Olfactory dysfunctions were significantly directly associated with current smoking and history of allergy, the multivariable ORs being 6.53 (95% CI 1.16-36.86) for current smokers versus never smokers, and 1.89 (95% CI 1.05-3.39) for those with an allergy compared to those without any allergy. Respiratory allergy in particular was significantly associated with olfactory dysfunctions (multivariable OR 2.30, 95% CI 1.02-5.17). Significant inverse associations were observed for patients aged 60 years or more (multivariable OR 0.33, 95% CI 0.19-0.57) and hospitalization (multivariable OR 0.22, 95% CI 0.06-0.89). Considering gustatory dysfunctions, after allowance of other variables a significant direct association was found for respiratory allergies (OR 2.24, 95% CI 1.03-4.86), and an inverse association was found only for hospitalization (OR 0.21, 95% CI 0.06-0.76).

CONCLUSION

Our study indicates that current smoking and history of allergy (particularly respiratory) significantly increase the risk for smell loss in COVID-19 patients; the latter is also significantly associated to taste loss. Hospitalization has an inverse association with the risk of olfactory and gustatory dysfunctions, suggesting that these may be symptoms characteristics of less severe SARS-CoV-2 infection.

Diagnostic prediction of COVID-19 based on clinical and radiological findings in a relatively low COVID-19 prevalence area

Background

Distinguishing coronavirus disease 2019 (COVID-19) pneumonia from other lung diseases is often difficult, especially in a highly comorbid patient population in a low prevalence region. We aimed to distinguish clinical data and computed tomography (CT) images between COVID-19 and other lung diseases in an advanced care hospital.

Methods

We assessed clinical characteristics, laboratory data, and chest CT images of patients with COVID-19 and non-COVID-19 patients who were suspected of having COVID-19 between February 20 and May 21, 2020, at the University of Tokyo Hospital.

Results

Typical appearance for COVID-19 on CT images were found in 24 of 29 COVID-19 cases and 21 of 168 non-COVID-19 cases, according to the Radiological Society of North America Expert Consensus Statement (for predicting COVID-19, sensitivity 0.828, specificity 0.875, positive predictive value 0.533, negative predictive value 0.967). When we focused on cases with typical CT images, loss of taste or smell, and close contact with COVID-19 patients were exclusive characteristics for the COVID-19 cases. Among laboratory data, high fibrinogen (P < 0.01) and low white blood cell count (P < 0.01) were good predictors for COVID-19 with typical CT images in multivariate analysis.

Conclusions

In a relatively low prevalence region, CT screening has high sensitivity to COVID-19 in patients with suspected symptoms. When chest CT findings are typical for COVID-19, close contact, loss of taste or smell, lower white blood cell count, and higher fibrinogen are good predictors for COVID-19.

Oral Symptoms Associated with COVID-19 and Their Pathogenic Mechanisms: A Literature Review

Since the worldwide spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, management of coronavirus disease 2019 (COVID-19) has been challenging for healthcare providers. The oral cavity is referred to as a target of SARS-CoV-2. The aim of this study was to review oral symptoms specific to COVID-19 patients from the point of view of symptom prevalence and pathogenesis and to speculate the pathogenic mechanisms underlying them. Scientific articles were retrieved by searching PubMed/MEDLINE, Google Scholar, medRxiv, and bioRxiv from 3 February 2020 to 31 December 2020, and they were reviewed by title, abstract, and text for relevance. The literature search indicated that COVID-19 patients frequently present with gustatory dysfunction, xerostomia, and oral mucosal lesions, while their prevalence is likely to vary by country, age, gender, and disease severity. Gustatory dysfunction and xerostomia appear at an early stage of SARS-CoV-2 infection and last relatively long. One of possible pathogenic mechanisms of both symptoms is attributed to the expression of viral cellular entry-relevant receptors in taste cells and salivary glands. Dental professionals who can first become aware of oral symptoms associated with COVID-19 will play a more active role in and make a greater contribution to diagnosis and prevention of COVID-19.

Onset and duration of symptoms of loss of smell/taste in patients with COVID-19: A systematic review

Objective

The aim of the study was to conduct a systematic review of the literature to investigate the time of onset and duration of symptoms of loss of smell and taste in patients diagnosed with COVID-19.

Methods

Two independent authors performed a systematic review of the Medline/PubMed, SCOPUS, COCHRANE, Lilacs and Web of Science electronic databases. The time of onset and duration of symptoms were considered primary outcomes. The sex and age of individuals, the geographical location of the study, the prevalence of symptoms, other associated symptoms, associated comorbidities, and the impact on quality of life and eating habits were considered secondary outcomes.

Results

Our search generated 17 articles. Many of the studies reported that the onset of anosmia and ageusia occurred 4 to 5 days after the manifestation of other symptoms of the infection and that these symptoms started to disappear after one week, with more significant improvements in the first two weeks.

Conclusion

The present study concludes that the onset of symptoms of loss of smell and taste, associated with COVID-19, occurs 4 to 5 days after other symptoms, and that these symptoms last from 7 to 14 days. Findings, however, varied and there is therefore a need for further studies to clarify the occurrence of these symptoms. This would help to provide early diagnosis and reduce contagion by the virus.

Neurological Consequences of SARS-CoV-2 Infection and Concurrence of Treatment-Induced Neuropsychiatric Adverse Events in COVID-19 Patients: Navigating the Uncharted

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to the angiotensin-converting enzyme 2 (ACE2) receptor and invade the human cells to cause COVID-19-related pneumonia. Despite an emphasis on respiratory complications, the evidence of neurological manifestations of SARS-CoV-2 infection is rapidly growing, which is substantially contributing to morbidity and mortality. The neurological disorders associated with COVID-19 may have several pathophysiological underpinnings, which are yet to be explored. Hypothetically, SARS-CoV-2 may affect the central nervous system (CNS) either by direct mechanisms like neuronal retrograde dissemination and hematogenous dissemination, or via indirect pathways. CNS complications associated with COVID-19 include encephalitis, acute necrotizing encephalopathy, diffuse leukoencephalopathy, stroke (both ischemic and hemorrhagic), venous sinus thrombosis, meningitis, and neuroleptic malignant syndrome. These may result from different mechanisms, including direct virus infection of the CNS, virus-induced hyper-inflammatory states, and post-infection immune responses. On the other hand, the Guillain-Barre syndrome, hyposmia, hypogeusia, and myopathy are the outcomes of peripheral nervous system injury. Although the therapeutic potential of certain repurposed drugs has led to their off-label use against COVID-19, such as anti-retroviral drugs (remdesivir, favipiravir, and lopinavir-ritonavir combination), biologics (tocilizumab), antibiotics (azithromycin), antiparasitics (chloroquine and hydroxychloroquine), and corticosteroids (dexamethasone), unfortunately, the associated clinical neuropsychiatric adverse events remains a critical issue. Therefore, COVID-19 represents a major threat to the field of neuropsychiatry, as both the virus and the potential therapies may induce neurologic as well as psychiatric disorders. Notably, potential COVID-19 medications may also interact with the medications of pre-existing neuropsychiatric diseases, thereby further complicating the condition. From this perspective, this review will discuss the possible neurological manifestations and sequelae of SARS-CoV-2 infection with emphasis on the probable underlying neurotropic mechanisms. Additionally, we will highlight the concurrence of COVID-19 treatment-associated neuropsychiatric events and possible clinically relevant drug interactions, to provide a useful framework and help researchers, especially the neurologists in understanding the neurologic facets of the ongoing pandemic to control the morbidity and mortality.

Identifying Risk Factors That Distinguish Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection From Common Upper Respiratory Infections in Children

Background Demographic and clinical risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children presenting with respiratory viral symptoms are not well defined. An understanding of risk factors for SARS-CoV-2 infection can help prioritize testing. Methodology We evaluated potential demographic and clinical factors in children who had respiratory viral symptoms and were tested by polymerase chain reaction (PCR) for SARS-CoV-2 and other respiratory viral infections. Results Among the 263 symptomatic children tested for routine seasonal respiratory viruses by PCR, 18 (6.8%) tested positive for SARS-CoV-2. Overall, 22.2% of SARS-CoV-2-infected children and 37.1% of SARS-CoV-2-uninfected children had infection with one or more non-SARS-CoV-2 pathogens (p = 0.31). Higher proportions of children with compared to without SARS-CoV-2 infection were male (77.8 vs. 51.8%, p = 0.05), Hispanic (44.4% vs. 9.8%, p < 0.001), or had the symptoms of fatigue (22.2% vs. 2.5%, p = 0.003) or anosmia/ageusia (11.1% vs. 0%, p = 0.004). History of hypoxic-ischemic encephalopathy (HIE) and obesity were more common in children with versus without SARS-CoV-2 infection (11.1% vs. 1.2%, p = 0.04, and 11.1% vs. 0%, p = 0.004, respectively). In a multivariate analysis, Hispanic ethnicity, symptoms of fatigue or anosmia/ageusia, and presence of obesity (as noted on physical examination) or HIE were independently associated with SARS-CoV-2 infection. Numbers in each category were small, and these preliminary associations require confirmation in future studies. Conclusions In this area of the United States, infection with other viruses did not rule out infection with SARS-CoV-2. Additionally, children with respiratory viral symptoms who were of Hispanic ethnicity, had symptoms of weakness/fatigue, or had obesity or HIE were at an increased risk for SARS-CoV-2 infection. Future studies should assess if these factors are associated with risk in populations in other areas of the United States.

Olfactory and Gustatory Dysfunction in COVID-19 Patients from Northern India: A Cross-Sectional Observational Study

Olfactory dysfunction (OD) and gustatory dysfunction (GD) has been reported as one of the presenting symptoms amongst COVID-19 patients. However the literature available is disjunct on this aspect. This study is conducted to identify the prevalence of olfactory and/or gustatory dysfunction in patients with coronavirus disease in Northern part of India. It’s a cross-sectional observation study, conducted over 387 COVID-19 positive patients, at ENT dept of tertiary care hospital. A retrospective survey was conducted using a pre designed questionnaire and details of Olfactory and Gustatory dysfunction was collected. The patient’s demographic details, disease course and recovery time for olfactory (OD) and/or gustatory dysfunctions (GD) were collected. A total of 387 patients with COVID-19 completed the study. 228 (58.9%) patients suffered from influenza like illness (ILI) (fever, sore throat, dry cough, malaise, and myalgia). There was significant positive association seen between with ILI and OD and / or GD. 167/387 (43.15%) patients reported OD, and 153/387 (39.53%) reported GD. 43.71% and 50.3% patients had mild OD & GD respectively. Recovery rates for both OD and GD are high and almost similar, with 161 (96.4%) and 148 (96.73%) patients had complete recovery of smell and taste. Maximum recovery was noticed between 4 and 6 weeks. COVID-19 patients with habits have significantly high probability of developing OD &/or GD. There is a significant correlation between OD and GD and there is high probability that patients who reported to have OD will also have GD or vice versa. Prevalence of OD and GD in Indian population may not be as high as mentioned in western literature, however, both are frequent and early symptoms of COVID-19. Recent onset of these should be considered as red flag symptoms for COVID-19.

Loss of Smell and Taste Can Accurately Predict COVID-19 Infection: A Machine-Learning Approach

The COVID-19 outbreak has spread extensively around the world. Loss of smell and taste have emerged as main predictors for COVID-19. The objective of our study is to develop a comprehensive machine learning (ML) modelling framework to assess the predictive value of smell and taste disorders, along with other symptoms, in COVID-19 infection. A multicenter case-control study was performed, in which suspected cases for COVID-19, who were tested by real-time reverse-transcription polymerase chain reaction (RT-PCR), informed about the presence and severity of their symptoms using visual analog scales (VAS). ML algorithms were applied to the collected data to predict a COVID-19 diagnosis using a 50-fold cross-validation scheme by randomly splitting the patients in training (75%) and testing datasets (25%). A total of 777 patients were included. Loss of smell and taste were found to be the symptoms with higher odds ratios of 6.21 and 2.42 for COVID-19 positivity. The ML algorithms applied reached an average accuracy of 80%, a sensitivity of 82%, and a specificity of 78% when using VAS to predict a COVID-19 diagnosis. This study concludes that smell and taste disorders are accurate predictors, with ML algorithms constituting helpful tools for COVID-19 diagnostic prediction.

Regional and Chronological Variation of Chemosensory Dysfunction in COVID-19: a Meta-Analysis

BACKGROUND

Olfactory and gustatory dysfunction are frequently reported in patients with coronavirus disease 2019 (COVID-19). However, the reported prevalence of olfactory and/or gustatory dysfunction varies widely, and the reason for the inter-study differences is unclear. Hence, in this meta-analysis, we performed subgroup analyses to investigate the factors that contribute to the inter-study variability in the prevalence of olfactory and gustatory dysfunction.

METHODS

Out of 943 citations, we included 55 eligible studies with 13,527 patients with COVID-19 for a meta-analysis. Calculating the data extracted from each study, the weighted summary prevalence of olfactory and gustatory dysfunction was estimated using a Freeman-Tukey transformation with models based on random-effects assumptions. A meta-analysis of variance compared the prevalence of olfactory and gustatory dysfunction according to regional, chronological, demographic, and methodologic factors, respectively.

RESULTS

The overall pooled prevalence rates of olfactory and gustatory dysfunction were 51.4% and 47.5%, respectively, in the random-effect model. In subgroup analyses, the prevalence rates of olfactory and gustatory dysfunction were significantly different among four geographical regions (both P < 0.001, respectively). Although the prevalence rates of olfactory and gustatory dysfunction did not significantly differ according to the time of enrollment, the subgroup analyses including only studies from the same geographical region (Europe) revealed a significant difference in olfactory dysfunction according to the time of enrollment.

CONCLUSION

The regional and chronological differences in the prevalence rates of olfactory and gustatory dysfunctions partly explain the wide inter-study variability.

Smell Status in Children Infected with SARS-CoV-2

OBJECTIVES/HYPOTHESIS

This study aimed to evaluate the olfactory status in children with laboratory confirmed SARS-CoV-2 using subjective and psychophysical methods.

STUDY DESIGN

Prospective clinical cross-sectional study.

METHODS

This is a prospective clinical cross-sectional study of 79 children with COVID-19. The 21st item of SNOT-22 questionnaire and odor identification test were used for smell assessment. Children were examined twice during the hospitalization, and a telephone survey was conducted 60 days after hospital discharge.

RESULTS

Immediately after confirmation of COVID-19, smell impairment was detected in 86.1% of children by means of the Identification test and in 68.4% of children by means of the survey (P = .010). After 5 days survey revealed a statistically significant decrease in the number of patients with hyposmia (41 out of 79, 51.9%). On the first visit, the mean Identification test score corresponded to "hyposmia" (9.5 ± 2.7), while on the second visit, the average value was 13.1 ± 1.9, which corresponded to "normosmia." According to the telephone survey, recovery of the olfactory function occurred within 10 days in 37 of 52 patients (71.2%), 11 to 29 days - in 12 children (23.1%), and later than 30 days - in three cases (5.7%).

CONCLUSIONS

In the pediatric population, olfactory dysfunction is an early and common symptom of COVID-19. There is a trend to quick recovery of olfactory function in children with COVID-19. The overwhelming majority of patients (94.3%) had no subjective olfactory complaints by the end of the first month.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2475-E2480, 2021.

Olfactory dysfunction in COVID-19: a marker of good prognosis?

Introduction

In May 2020, the World Health Organization recognized olfactory dysfunction as a COVID-19 symptom. The presence of hyposmia/anosmia may be a marker of good prognosis in COVID-19.

Objective

To associate the presence of olfaction disorder to the clinical condition severity in patients with COVID-19.

Methods

Individuals with the flu syndrome caused by SARS-CoV-2, diagnosed from March to June 2020, were recruited. They were divided into three groups: mild flu syndrome, severe flu syndrome (admitted to hospital wards) and critical illness (admitted to the ICU). Inpatients were interviewed by telephone contact after hospital discharge and their medical records were also evaluated regarding complementary test results. Outpatients answered an electronic questionnaire containing only clinical information.

Results

A total of 261 patients participated in the study: 23.75% with mild flu syndrome, 57.85% with severe flu syndrome and 18.40% with critical illness. A total of 66.28% patients with COVID-19 had olfaction disorders. In approximately 56.58% of the individuals the smell alterations lasted between 9 days and 2 months. There was a significantly higher proportion of individuals with olfactory dysfunction in the group with mild flu syndrome than in the severe flu syndrome group (mild × severe – p < 0.001; Odds Ratio = 4.63; 95% CI [1.87–10.86]). This relationship was also maintained between patients with mild flu syndrome and critically-ill patients (mild × critical – p <  0.001; Odds Ratio = 9.28; 95% CI [3.52–25.53]).

Conclusion

Olfaction dysfunction was significantly more prevalent in patients with mild flu syndrome in COVID-19. It may be a predictor of a good prognosis for this infection. New population-based studies must be carried out to corroborate these findings.

Clinical significance of smell and taste dysfunction and other related factors in COVID-19

PURPOSE

The objective of this study is to evaluate smell and taste dysfunction (STD) in coronavirus disease 2019 (COVID-19) positive and negative patients, and to assess the factors associated with STD in COVID-19 positive patients.

METHODS

Patients who had been tested with the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for COVID-19 were identified, and according to the RT-PCR test results, patients were separated into Positive and Negative Groups. A telephone-based assessment was applied to both groups using the American Academy of Otolaryngology-Head and Neck Surgery Anosmia Reporting Tool. Patients in Positive Group were also asked to rate STD, nasal breathing, and anxiety in three different time periods (pre-/during-/post-COVID) using the visual analog scale (VAS).

RESULTS

A total of 53 COVID-19 positive and 51 negative patients completed the surveys. STD was eightfold more frequent (OR 8.19; CI 95% 3.22-20.84) in the Positive Group. Of the 53 COVID-19 positive patients, 32 reported STD and 21 did not. 'Ground-glass appearance' on chest-computed tomography was more frequent and median lymphocyte count was significantly lower in COVID-19 positive patients with STD. During-COVID STD and nasal breathing VAS scores were significantly lower than the pre- and post-COVID scores. During-COVID STD scores were significantly correlated with anxiety scores (Spearman's rho-0.404, p = 0.022) but not correlated with nasal breathing scores.

CONCLUSION

STD may be related to increased inflammatory response as well as damage of olfactory neuronal pathway or non-neuronal olfactory mucosa. Understanding the exact cause of chemosensory impairment in COVID-19 can be helpful in explaining the pathophysiology of the disease.

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

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.

Gaining Back What Is Lost: Recovering the Sense of Smell in Mild to Moderate Patients After COVID-19

The purpose of our cohort study was to quantify olfactory deficits in Coronavirus disease 2019 (COVID-19) patients using Sniffin' Sticks and a pre-post design to evaluate olfactory recovery. Thirty adult patients with laboratory-confirmed mild to moderate forms of COVID-19 underwent a quantitative olfactory test performed with the Sniffin' Sticks test (SST; Burghardt, Wedel, Germany), considering olfactory threshold (T), odor discrimination (D), and odor identification (I). Results were presented as a composite TDI score (range 1-48) that used to define functional anosmia (TDI ≤ 16.5), hyposmia (16.5 < TDI < 30.5), or functionally normal ability to smell (TDI ≥ 30.5). Patients also self-evaluated their olfactory function by rating their ability to smell on a visual analogue scale (Visual Analog Scale rating) and answering a validated Italian questionnaire (Hyposmia Rating Scale). Patients were tested during hospitalization and about 2 months after symptoms onset. During the hospitalization, the overall TDI score indicated that our cohort had impairments in their olfactory ability (10% was diagnosed with anosmia and more than 50% were hyposmic). Almost all patients showed a significant improvement at around 1 month following the first test and for all the parts of the SST except for odor identification. None of the subjects at 1 month was still diagnosed with anosmia. We also quantified the improvement in the TDI score based on initial diagnosis. Anosmic subjects showed a greater improvement than hyposmic and normosmic subjects. In conclusion, within a month time window and 2 months after symptoms' onset, in our cohort of patients we observed a substantial improvement in the olfactory abilities.

Loss of Olfactory Function-Early Indicator for Covid-19, Other Viral Infections and Neurodegenerative Disorders

The loss of the senses of smell (anosmia) and taste (ageusia) are rather common disorders, affecting up to 20% of the adult population. Yet, this condition has not received the attention it deserves, most probably because per se such a disorder is not life threatening. However, loss of olfactory function significantly reduces the quality of life of the affected patients, leading to dislike in food and insufficient, exaggerated or unbalanced food intake, unintentional exposure to toxins such as household gas, social isolation, depression, and an overall insecurity. Not only is olfactory dysfunction rather prevalent in the healthy population, it is, in many instances, also a correlate or an early indicator of a panoply of diseases. Importantly, olfactory dysfunction is linked to the two most prominent neurodegenerative disorders, Parkinson's disease and Alzheimer's disease. Anosmia and hyposmia (reduced sense of smell) affect a majority of patients years before the onset of cognitive or motor symptoms, establishing olfactory dysfunction as early biomarker that can enable earlier diagnosis and preventative treatments. In the current health crisis caused by SARS-CoV2, anosmia and dysgeusia as early-onset symptoms in virus-positive patients may prove to be highly relevant and crucial for pre-symptomatic Covid-19 detection from a public health perspective, preceding by days the more classical respiratory tract symptoms such as cough, tightness of the chest or fever. Thus, the olfactory system seems to be at the frontline of pathologic assault, be it through pathogens or insults that can lead to or at least associate with neurodegeneration. The aim of this review is to assemble current knowledge from different medical fields that all share a common denominator, olfactory/gustatory dysfunction, and to distill overarching etiologies and disease progression mechanisms.

Otolaryngologic Manifestation and Long-Term Outcome in Mild COVID-19: Experience from a Tertiary Care Centre in India

This study endeavours to comprehensively the study the spectrum of ENT manifestations in mild and asymptomatic COVID-19 and observe the natural course of anosmia and dysgeusia consequent to SARS-Cov-2 infection. A prospective cohort study was undertaken at a tertiary care centre in India on admitted patients with RT-PCR proven COVID-19. Patients were included provided the baseline National Early Warning Score (NEWS) was less than 4. Patients were screened for ENT manifestations using a questionnaire at baseline, 7 days, 14 days and 28 days. 225 patients were included in the study. Of these complete data at 4 weeks was available for 210. Out of 145 patients with mild COVID-19 (asymptomatic = 80), ENT manifestations accounted for 66.2% of all symptoms. Smell and taste disturbance had an overall incidence of 20% and 45% of ENT manifestations. Temporal trends of the recovery rate of anosmia and dysgeusia were 53.6% and 66.7% at 2 weeks, respectively. Corresponding rates at 3 weeks were 89.29% and 86.7%, respectively. By the end of 4 weeks 96% of the patients had recovered completely. The incidence of anosmia and dysgeusia in this study parallels the rates reported from other Asian countries, albeit, lower than the rates quoted from the Western Hemisphere. We recommend structured reporting of all ENT manifestations especially smell and taste disturbances to accurately identify individuals infected with SARS-Cov-2.

Frequency and Clinical Utility of Olfactory Dysfunction in COVID-19: a Systematic Review and Meta-analysis

Background

Olfactory dysfunction (OD) has been gaining recognition as a symptom of COVID-19, but its clinical utility has not been well defined.

Objectives

To quantify the clinical utility of identifying OD in the diagnosis of COVID-19 and determine an estimate of the frequency of OD amongst these patients.

Methods

PubMed was searched up to 1 August 2020. Meta-analysis A included studies if they compared the frequency of OD in COVID-19 positive patients (proven by reverse transcription polymerase chain reaction) to COVID-19 negative controls. Meta-analysis B included studies if they described the frequency of OD in COVID-19 positive patients and if OD symptoms were explicitly asked in questionnaires or interviews or if smell tests were performed.

Results

The pooled frequency of OD in COVID-19 positive patients (17,401 patients, 60 studies) was 0.56 (0.47–0.64) but differs between detection via smell testing (0.76 [0.51–0.91]) and survey/questionnaire report (0.53 [0.45–0.62]), although not reaching statistical significance (p = 0.089). Patients with reported OD were more likely to test positive for COVID-19 (diagnostic odds ratio 11.5 [8.01–16.5], sensitivity 0.48 (0.40 to 0.56), specificity 0.93 (0.90 to 0.96), positive likelihood ratio 6.10 (4.47–8.32) and negative likelihood ratio 0.58 (0.52–0.64)). There was significant heterogeneity amongst studies with possible publication bias.

Conclusion

Frequency of OD in COVID-19 differs greatly across studies. Nevertheless, patients with reported OD were significantly more likely to test positive for COVID-19. Patient-reported OD is a highly specific symptom of COVID-19 which should be included as part of the pre-test screening of suspect patients.

Prevalence of Chemosensory Dysfunction in COVID-19 Patients: A Systematic Review and Meta-analysis Reveals Significant Ethnic Differences

A significant proportion of people who test positive for COVID-19 have chemosensory deficits. However, the reported prevalence of these deficits in smell and taste varies widely, and the reason for the differences between studies is unclear. We determined the pooled prevalence of such chemosensory deficits in a systematic review and meta-analysis. We searched the COVID-19 portfolio of the National Institutes of Health for studies that reported the prevalence of smell or taste deficits or both in patients diagnosed with COVID-19. One-hundred-four studies reporting on 38 198 patients qualified and were subjected to a systematic review and meta-analysis. Estimated random prevalence of olfactory dysfunction was 43.0%, that of taste dysfunction was 44.6%, and that of overall chemosensory dysfunction was 47.4%. We examined the effects of age, gender, disease severity, and ethnicity on chemosensory dysfunction. Prevalence of smell or taste dysfunction or both decreased with older age, male gender, and disease severity. Ethnicity was highly significant: Caucasians had a three times higher prevalence of chemosensory dysfunctions (54.8%) than Asians (17.7%). The finding of geographic differences points to two causes that are not mutually exclusive. A virus mutation (D614G) may cause differing infectivity, while at the host level genetic, ethnicity-specific variants of the virus-binding entry proteins may facilitate virus entry in the olfactory epithelium and taste buds. Both explanations have major implications for infectivity, diagnosis, and management of the COVID-19 pandemic.

Contemporary Analysis of Olfactory Dysfunction in Mild to Moderate Covid 19 Patients in A Tertiary Health Care Centre

Introduction: The World Health Organization declared COVID-19 a pandemic on March 11, 2020. The virus that causes COVID-19 was designated as severe acute respiratory syndrome corona virus 2 (SARS-CoV-2). Several studies have reported chemosensory dysfunction, such as anosmia and ageusia, as common findings in COVID-19 positive patients. To date, qualitative olfactory testing has been performed only in a very few cohort studies on COVID-19 patients. However, objective testing is necessary to verify or determine the true magnitude of their deficits. Moreover, the proportion of COVID-19 patients exhibiting true olfactory disturbances is unknown. Aim of the Study: To determine the true prevalence of olfactory dysfunction in COVID-19 patients by objective assessment in mild to moderate symptomatic patients. Materials & Methodology: This was a prospective cross-sectional analytical study. All patients who were COVID-19 positive and having mild to moderate symptoms and not admitted in ICU formed part of the study group. Objective evaluation of smell function was done. Results: Self-reported smell dysfunction was present in 26.9% patients (n=62) and taste dysfunction was seen in 10.9% (n=25) of patients. On quantitative assessment of smell dysfunction, it was noted that 41.3% (n=95) of patients had some form of smell dysfunction out of which 70.5% patients (n=67) had hyposmia and 29.5% patients (n=28) had anosmia. Conclusion: Incidence was found to be more by objective assessment when compared to self-reported symptoms.

Prevalence and recovery time of olfactory and gustatory dysfunction in hospitalized patients with COVID‑19 in Wuhan, China

Objective

To investigate olfactory and gustatory dysfunction in patients with coronavirus disease 2019 (COVID-19) in Wuhan using a telephone interview.

Methods

This retrospective telephone survey investigated 196 consecutive patients with COVID-19 at 3 months after discharge from two hospitals in Wuhan, China. The characteristics of the patient’s disease course and time to recovery from olfactory and/or gustatory dysfunction (OD and/or GD) were collected by telephone interview. Demographic data were collected from the patient medical records.

Results

A total of 196 patients with COVID-19 completed the study. The most prevalent general symptoms were fever, cough, and fatigue. Overall, 19.9% of the patients reported OD and/or GD. In 87.2% of these cases, OD or GD appeared after the general symptoms. The time to recovery from OD and/or GD was more than 4 weeks in 51.4% of the patients. Patients with COVID-19 and OD and/or GD had significantly higher rates of cardiovascular disease than patients without OD and/or GD (p = 0.002).

Conclusions

Recovery from chemosensory dysfunction (OD and/or GD) was slow, with over half of the patients taking more than 4 weeks to recover. Cardiovascular disease might be related to the development of olfactory or taste disorders in patients with COVID-19.

The Significance of Natural Product Derivatives and Traditional Medicine for COVID-19

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, there have been more than 10 million reported cases, more than 517,000 deaths in 215 countries, areas or territories. There is no effective antiviral medicine to prevent or treat COVID-19. Natural products and traditional medicine products with known safety profiles are a promising source for the discovery of new drug leads. There is increasing number of publications reporting the effect of natural products and traditional medicine products on COVID-19. In our review, we provide an overview of natural products and their derivatives or mimics, as well as traditional medicine products, which were reported to exhibit potential to inhibit SARS-CoV-2 infection in vitro, and to manage COVID-19 in vivo, or in clinical reports or trials. These natural products and traditional medicine products are categorized in several classes: (1) anti-malaria drugs including chloroquine and hydroxychloroquine, (2) antivirals including nucleoside analogs (remdesivir, favipiravir, β-D-N4-hydroxycytidine, ribavirin and among others), lopinavir/ritonavir and arbidol, (3) antibiotics including azithromycin, ivermectin and teicoplanin, (4) anti-protozoal drug, emetine, anti-cancer drug, homoharringtonine, and others, as well as (5) traditional medicine (Lian Hua Qing Wen Capsule, Shuang Huang Lian Oral Liquid, Qingfei Paidu Decoction and Scutellariae Radix). Randomized, double-blind and placebo-controlled large clinical trials are needed to provide solid evidence for the potential effective treatment. Currently, drug repurposing is a promising strategy to quickly find an effective treatment for COVID-19. In addition, carefully combined cocktails need to be examined for preventing a COVID-19 pandemic and the resulting global health concerns.

The clinical course of smell and taste loss in COVID-19 hospitalized patients

BACKGROUND

Recent studies have demonstrated an association between a new onset of smell or taste loss and COVID-19. We investigated the prevalence of smell and/or taste loss and the clinical characteristics and recovery in a comprehensive cohort of consecutive patients treated by two COVID-19 reference hospitals and evaluated late persistence of hyposmia.

METHODS

A retrospective observational questionnaire study was conducted. All consecutive RT-PCR diagnosed patients who had been hospitalized in March-April 2020 in the COVID-19 care wards were contacted, excluding patients with cognitive disorders and severe deconditioning. The patients responded to a survey about the loss of smell and taste, nasal blockage, and rhinorrhea, rated the symptoms' severity from 0 to 4, and reported the recovery of smell and taste with time. Demographic and clinical characteristics were recorded.

RESULTS

We contacted 117 patients. Ninety responded to the questionnaire; 38.9 % of them reported olfactory and 36.66 % gustatory disorders during their disease. Smell loss prior to other symptoms was reported by 42.86 %, and severe hyposmia/anosmia by 74.28 % of the hyposmic. Among the non-ICU treated patients, 43.75 % reported hyposmia. Only 8.89 % had nasal blockage, and 6.66 % rhinorrhea. Most of the patients (85.71 %) recovered their sense of smell in 3-61 days (median: 17; IQR: 24), but 8.57 % had persistent hyposmia. For one out of four, the olfactory loss lasted longer than a month.

CONCLUSION

Smell and taste loss are highly prevalent and early symptoms in hospitalized COVID-19 patients. The great majority recover their smell, but nearly one out of ten have not recovered in two months.  HIPPOKRATIA 2020, 24(2): 66-71.