Evolution of Olfactory Disorders in COVID-19 Patients

Recovery Patterns of COVID-19 Related Smell Disorders: An Analysis of the Available Evidence

Recently acquired olfactory dysfunction (OD) has emerged as one of hallmark manifestations of the novel Corona virus disease (COVID-19), but the evolution of its spontaneous recovery has remained inconclusive, with reports of persistence of OD beyond six months of onset. We undertook this systematic review and meta-analysis with a view to generating a pooled recovery rate of COVID-19 associated olfactory dysfunctions and attempt to examine the predictors of olfactory recovery. Systematic review and meta-analysis. A systematic search of Scopus, Google Scholar, and PubMed data bases, comprising all longitudinal studies reporting the trajectory of COVID-19 related OD was carried out. The pooled recovery rate was estimated with random-effects model, and the potential heterogeneity of the subgroup sources was analyzed using meta-regression test. After the PRISMA selection process 28 studies from 16 countries were included, with a total of 5,175 OD patients, among 11,948 COVID-19 cases. The estimated global pooled recovery rate of OD was 82.7% (95% CI, 77.46%-88.04%), with a pooled median duration of OD of 11.6 days. Only 2 out of 28 studies had recovery data beyond a period of 2 months. But no significant difference was found in the recovery rate regarding the length of follow up (P = 0.840). Studies that conducted objective olfactory assessments showed significant higher recovery rate than those with subjective assessments (P = 0.001). Although ten studies (36%) reported > 90% recovery, nine studies (32%) documented persistence of OD in > 25% of their patients. Five out of 6 studies showed that hyposmia tended to show complete recovery than anosmia. Age, co-morbidities, and intra-nasal treatments had no effects. Test of homogeneity between subgroups using the Cochran's Q test was not significant (Q = 0.69, P = 0.40). Our meta-analysis revealed high rate of early and medium term recovery of COVID-19 related OD. However, it also showed disturbing rates of persistence of OD. Anosmia tended to be predictive of residual OD than hyposmia. Age, co-morbidities, intra-nasal corticosteroid and decongestants, had no effects on OD recovery.

Olfactory dysfunction among patients with COVID-19

OBJECTIVES

To assess the frequency of olfactory dysfunction (OD) among individuals afflicted with coronavirus disease of 2019 (COVID-19).

METHODS

A comprehensive literature search was carried out across several bibliographical databases (PubMed, Scopus, Google Scholar, and Web of Science) to extract publications in the English language between January 2020 and December 2021 to report the incidence of OD alone or together with gustatory dysfunction (GD) among COVID-19 patients.

RESULTS

Based on eligibility criteria, 84 articles were included from 27 countries, comprising 36,903 patients, of whom 58.1% were females. The generality rates of olfactory impairment alone was 34.60% and in conjunction with GD was 11.36%. Patients with OD were subclassified into various categories, and the prevalence of anosmia was 20.85%, 5.04% for hyposmia, 8.88% for anosmia or hyposmia, 1.84% for parosmia, 0.78% for phantosmia, and 0.02% for hyperosmia, among COVID-19 patients.

CONCLUSION

Clinical features associated with OD, either isolated or in combination with GD, are common in patients with COVID-19 and consider important signs of COVID-19 that may guide clinicians in the early phase of the disease.PROSPERO Reg. No.: 417296.

Exhaled Nitric Oxide and Olfactory Dysfunction in Patients with Asthma: Association with Chronic Rhinosinusitis

Objectives: Olfactory dysfunction is a clinical sign that is important to detect with coexistent upper airway comorbidities in patients with asthma. This study aimed to investigate the etiology of olfactory dysfunction in patients with asthma and the relationship between fractional exhaled nitric oxide (FeNO) levels. Materials and Methods: This study included 47 asthma patients who were evaluated for olfactory dysfunction at Hiroshima University Hospital between 2012 and 2020. The etiologies of olfactory dysfunction were evaluated, and they were classified according to the FeNO levels of patients with asthma. Results: Olfactory dysfunction was observed in 30 patients with asthma, with chronic rhinosinusitis (77%) being the most prevalent etiology. Eosinophilic chronic rhinosinusitis (ECRS) was the most prevalent etiology of olfactory dysfunction in asthma patients with high FeNO levels (≥25 ppb), while non-eosinophilic chronic rhinosinusitis (NCRS) was the most prevalent etiology in asthma patients with low FeNO levels (<25 ppb). Additionally, the prevalence of ECRS was significantly higher in asthma patients with olfactory dysfunction and high FeNO levels (74%) than in those with either high FeNO levels or olfactory dysfunction and those with low FeNO levels and no olfactory dysfunction (12% and 9%, respectively). Conclusions: We found that ECRS was the predominant cause of olfactory dysfunction in patients with high FeNO levels, while NCRS was more common in those with low FeNO levels. The present study showed that both ECRS and NCRS are common etiologies of olfactory dysfunction in patients with asthma. Additionally, this study supports the link between upper and lower airway inflammation in patients with asthma complicated with olfactory dysfunction.

Neurological complications and effects of COVID-19: Symptoms and conceivable mechanisms

A novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first identified in December 2019 in Wuhan, China. The new coronavirus disease (COVID-19) was declared a global pandemic by the World Health Organization (WHO) in March 2020. SARS-CoV-2 can invade the nervous system aside from infecting the respiratory system as its primary target. The most common nervous system symptoms of COVID-19 are stated as headache, myalgia, fatigue, nausea, vomiting, sudden and unexplained anosmia, and ageusia. More severe conditions such as encephalomyelitis, acute myelitis, thromboembolic events, ischemic stroke, intracerebral hemorrhage, Guillain-Barré-syndrome, Bell's palsy, rhabdomyolysis, and even coma have also been reported. Cohort studies revealed that neurological findings are associated with higher morbidity and mortality. The neurological symptoms and manifestations caused by SARS-CoV-2 and COVID-19 are examined and summarized in this article.

The assessment of qualitative olfactory dysfunction in COVID-19 patients: a systematic review of tools and their content validity

Background

There is a lack of overview of the tools used to assess qualitative olfactory dysfunction, including parosmia and phantosmia, following COVID-19 illness. This could have an impact on the diagnosis and treatment offered to patients. Additionally, the formulations of symptoms are inconsistent and often unclear, and consensus around the wording of questions and responses is needed.

Aim of study

The aim of this systematic review is to provide an overview of tools used to assess qualitative olfactory dysfunction after COVID-19, in addition to addressing the content validity (i.e., item and response formulations) of these tools.

Methods

MEDLINE, Web of Science, and EMBASE were searched 5th of August 2022 and updated on the 25th of April 2023 to identify studies that assess qualitative olfactory dysfunction in COVID-19 patients. Primary outcomes were the tool used (i.e., questionnaire or objective test) and item and response formulations. Secondary outcomes included psychometric properties, study design, and demographic variables.

Results

The assessment of qualitative olfactory dysfunction is characterized by heterogeneity, inconsistency, and lack of validated tools to determine the presence and degree of symptoms. Several tools with overlapping and distinct features were identified in this review, of which some were thorough and detailed, while others were merely assessing the presence of symptoms as a binary measure. Item and response formulations are also inconsistent and often used interchangeably, which may lead to confusion, incorrect diagnoses, and inappropriate methods for solving the problem.

Conclusions

There is an unmet need for a reliable and validated tool for assessing qualitative olfactory dysfunction, preferably one that also captures quantitative olfactory issues (i.e., loss of smell), to ensure time-effective and specific assessment of the ability to smell. A consensus around the formulation of items and response options is also important to increase the understanding of the problem, both for clinicians, researchers, and the patient, and ultimately to provide the appropriate diagnosis and treatment.

Registration and protocol

The URL is https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=351621. A preregistered protocol was submitted and accepted (12.09.22) in the International prospective register of systematic reviews (PROSPERO) with the registration number CRD42022351621.

Efficacy of pentasodium diethylenetriamine pentaacetate in ameliorating anosmia post COVID-19

BACKGROUND

COVID-19 has been frequently demonstrated to be associated with anosmia. Calcium cations are a mainstay in the transmission of odor. One of their documented effects is feedback inhibition. Thus, it has been advocated that reducing the free intranasal calcium cations using topical chelators such as pentasodium diethylenetriamine pentaacetate (DTPA) could lead to restoration of the olfactory function in patients with post-COVID-19 anosmia.

METHODOLOGY

This is a randomized controlled trial that investigated the effect of DTPA on post-COVID-19 anosmia. A total of 66 adult patients who had confirmed COVID-19 with associated anosmia that continued beyond three months of being negative for SARS-CoV-2 infection. The included patients were randomly allocated to the control group that received 0.9 % sodium chloride-containing nasal spray or the interventional group that received 2 % DTPA-containing nasal spray at a 1:1 ratio. Before treatment and 30 days post-treatment, the patients' olfactory function was evaluated using Sniffin' Sticks, and quantitative estimation of the calcium cations in the nasal mucus was done using a carbon paste ion-selective electrode test.

RESULTS

Patients in the DTPA-treated group significantly improved compared to the control group in recovery from functional anosmia to hyposmia. Additionally, they showed a significant post-treatment reduction in the calcium concentration compared to the control group.

CONCLUSION

This study confirmed the efficacy of DTPA in treating post-COVID-19 anosmia.

Short Communication: Stellate Ganglion Blockade for Persistent Olfactory and Gustatory Symptoms Post-COVID-19

One hundred ninety-five patients presenting with post-COVID symptomology, including parosmia and dysgeusia, underwent reversible stellate ganglion blockade. Stellate ganglion blockade was performed at an outpatient facility, and patients were evaluated via survey at seven days post-injection. Of the 195 participants, ages ranged from 18-69 years of age with the breakdown of sexes being females n = 157 and males n = 38. The most significant finding was a reported improvement in olfaction post-injection in 87.4% of subjects. The effectiveness of this novel treatment for post-COVID is promising and warrants further investigation.

Taste loss as a distinct symptom of COVID-19: a systematic review and meta-analysis

Chemosensory scientists have been skeptical that reports of COVID-19 taste loss are genuine, in part because before COVID-19 taste loss was rare and often confused with smell loss. Therefore, to establish the predicted prevalence rate of taste loss in COVID-19 patients, we conducted a systematic review and meta-analysis of 376 papers published in 2020-2021, with 235 meeting all inclusion criteria. Drawing on previous studies and guided by early meta-analyses, we explored how methodological differences (direct vs. self-report measures) may affect these estimates. We hypothesized that direct measures of taste are at least as sensitive as those obtained by self-report and that the preponderance of evidence confirms taste loss is a symptom of COVID-19. The meta-analysis showed that, among 138,015 COVID-19-positive patients, 36.62% reported taste dysfunction (95% confidence interval: 33.02%-40.39%), and the prevalence estimates were slightly but not significantly higher from studies using direct (n = 15) versus self-report (n = 220) methodologies (Q = 1.73, df = 1, P = 0.1889). Generally, males reported lower rates of taste loss than did females, and taste loss was highest among middle-aged adults. Thus, taste loss is likely a bona fide symptom of COVID-19, meriting further research into the most appropriate direct methods to measure it and its underlying mechanisms.

Olfactory dysfunction in COVID-19, new insights from a cohort of 353 patients: The ANOSVID study

Olfactory disorders (OD) pathogenesis, underlying conditions, and prognostic in coronavirus disease 2019 (COVID-19) remain partially described. ANOSVID is a retrospective study in Nord Franche-Comté Hospital (France) that included COVID-19 patients from March 1 2020 to May 31 2020. The aim was to compare COVID-19 patients with OD (OD group) and patients without OD (no-OD group). A second analysis compared patients with anosmia (high OD group) and patients with hyposmia or no OD (low or no-OD group). The OD group presented less cardiovascular and other respiratory diseases compared to the no-OD group (odds ratio [OR] = 0.536 [0.293-0.981], p = 0.041 and OR = 0.222 [0.056-0.874], p = 0.037 respectively). Moreover, history of malignancy was less present in the high OD group compared with the low or no-OD group (OR = 0.170 [0.064-0.455], p < 0.001). The main associated symptoms (OR > 5) with OD were loss of taste (OR = 24.059 [13.474-42.959], p = 0.000) and cacosmia (OR = 5.821 [2.246-15.085], p < 0.001). Most of all ORs decreased in the second analysis, especially for general, digestive, and ENT symptoms. Only two ORs increased: headache (OR = 2.697 [1.746-4.167], p < 0.001) and facial pain (OR = 2.901 [1.441-5.842], p = 0.002). The high OD group had a higher creatinine clearance CKD than the low or no-OD group (89.0 ± 21.1 vs. 81.0 ± 20.5, p = 0.040). No significant difference was found concerning the virological, radiological, and severity criteria. OD patients seem to have less comorbidity, especially better cardiovascular and renal function. Associated symptoms with OD were mostly neurological symptoms. We did not find a significant relationship between OD and less severity in COVID-19 possibly due to methodological bias.

Anatomophysiological relationships and clinical considerations of taste and smell loss in patients with COVID-19

BACKGROUND

There are numerous conflicting discussions about the outbreak of the new coronavirus 2019 (COVID-19).

AIM

To present some anatomical and physiological considerations about two of the symptoms reported by patients: The loss or reduction of smell and taste.

METHODS

The loss or reduction of smell and taste is presented in a peculiar way, with some cases of persistence even after COVID-19. For this, it was searched in three databases, PubMed/MEDLINE, Web of Science, and Scopus, using the following keywords: "Smell", "Taste", "Smell AND COVID-19", "Taste AND COVID-19", with no publication time restriction, only in English with full text available, excluding also brief communications, letters to the editor, editorials, reviews, comments, and conference abstracts.

RESULTS

The search found 776 articles in the PubMed/MEDLINE database, 1018 in the Web of Science database, and 552 in the Scopus database, from which duplicates were removed (104 articles). Finally, 17 studies were selected for detailed analysis within the eligibility criteria, with titles and abstracts related to central nervous system lesions responsible for smell and taste. This review suggests that viral mechanisms of action may be related to lesions both at the local level and at the level of the central nervous system, lasting up to 3 to 4 wk. It is considered persistent if it exceeds this period, as reported in one case in this review. There are still few studies about the treatment, and among those addressed in this review, only two studies reported possible treatments and emphasized the scarcity of data, with the best option being treatments that do not cause harm, such as gustatory and olfactory physiotherapy

CONCLUSION

Given the scarcity of data, this review emphasizes the importance of prevention, through the correct use of personal protective equipment by health professionals and respect for local behavioral indications. It is also emphasized, through five studies, that there is a predominance of such symptoms in patients with COVID-19, which can be a tool to control dissemination, through the early isolation of patients until the results are ready.

The Effect of Topical Aminophylline on Hyposmia and Anosmia

Introduction

Olfactory training is accounted as a significantly beneficial therapy for hyposmia or anosmia. There is some evidence about methylxanthine usage for this issue. In the present study, we have investigated the effects of topical aminophylline in hyposmic and anosmic patients.

Materials and Methods

In this clinical trial study, patients were randomly divided into two groups (n= 20/each), the case group was given aminophylline drops over a three-month period (using the contents of the vial aminophylline in the form of nasal drops, 250 micrograms daily) with olfactory training and the control group was given normal saline drops with olfactory training over a three-month period. The olfactory capacities were assessed before the start and after the completion of treatments using a valid and reliable smell identification test.

Results

In the saline and aminophylline groups, the mean ± SD relative changes in SIT score were 0.55±0.31 and 0.85±0.56, respectively. As a result, the SIT score in the saline group climbed by 55 percent but increased by 85 percent in the aminophylline group. The difference in SIT score between pre- and post-test was meaningful in both groups (P< 0.001). The aminophylline group scored significantly higher according to the marginal longitudinal regression model, adjusting baseline parameters.

Conclusions

Intranasal aminophylline plus olfactory training significantly improved SIT scores in severe hyposmia or anosmia. Hypothetically, these effects are mediated through changes in cAMP and cGMP.

Intranasal delivery of SARS-CoV-2 spike protein is sufficient to cause olfactory damage, inflammation and olfactory dysfunction in zebrafish

Anosmia, loss of smell, is a prevalent symptom of SARS-CoV-2 infection. Anosmia may be explained by several mechanisms driven by infection of non-neuronal cells and damage in the nasal epithelium rather than direct infection of olfactory sensory neurons (OSNs). Previously, we showed that viral proteins are sufficient to cause neuroimmune responses in the teleost olfactory organ (OO). We hypothesize that SARS-CoV-2 spike (S) protein is sufficient to cause olfactory damage and olfactory dysfunction. Using an adult zebrafish model, we report that intranasally delivered SARS-CoV-2 S RBD mostly binds to the non-sensory epithelium of the olfactory organ and causes severe olfactory histopathology characterized by loss of cilia, hemorrhages and edema. Electrophysiological recordings reveal impaired olfactory function to both food and bile odorants in animals treated intranasally with SARS-CoV-2 S RBD. However, no loss of behavioral preference for food was detected in SARS-CoV-2 S RBD treated fish. Single cell RNA-Seq of the adult zebrafish olfactory organ indicated widespread loss of olfactory receptor expression and inflammatory responses in sustentacular, endothelial, and myeloid cell clusters along with reduced numbers of T_regs. Combined, our results demonstrate that intranasal SARS-CoV-2 S RBD is sufficient to cause structural and functional damage to the zebrafish olfactory system. These findings may have implications for intranasally delivered vaccines against SARS-CoV-2.

How common are taste and smell abnormalities in COVID-19? A systematic review and meta-analysis

OBJECTIVE

Olfactory and gustatory dysfunction (OGD) are important early clinical symptoms of COVID-19. We aim to calculate the pooled prevalence of these symptoms and discuss the likely implications on clinical practice such as their use as screening tools and potential prognosis indicators.

METHODS

Using a combination of keywords and medical subject headings, we searched for observational studies in the following five databases: Medline/PubMed, Scopus, Cochrane Library, Web of Science, and Google Scholar. Two authors independently screened and selected the final articles according to the inclusion criteria. Two investigators independently assessed the risk of bias in individual studies using the Newcastle-Ottawa Scale. Heterogeneity and publication bias were also assessed. The reported outcome of the pooled analysis was the prevalence of OGD calculated using a random-effect model. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to report results.

RESULTS

Seventeen studies with a total sample size of 4149 were included in this meta-analysis. Out of these, 2106 and 2676 patients reported some degree of olfactory and/or gustatory dysfunction with COVID-19, respectively. The reported outcomes were in terms of pooled prevalence, with gustatory dysfunction being 57.33% and olfactory dysfunction being 59.69%, a significantly high occurrence.

CONCLUSION

There is a high occurrence of smell and taste impairment in COVID-19. Given the lack of objective testing for detecting OGD in most studies, the high prevalence found is likely to be an underestimation of the true prevalence. This implies that physicians must use them as reliable early indicators of COVID-19 and employ them before using expensive tests.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Results from psychophysical tests of smell and taste during the course of SARS-CoV-2 infection: a review

Only a few studies have assessed smell and taste in Coronavirus Disease 2019 (COVID-19) patients with psychophysical tests, while the majority performed self-rating evaluations. Given the heterogeneity of the published literature, the aim of this review was to systematically analyse the articles on this topic with a focus on psychophysical testing. A search on PubMed and Web of Science from December 2019, to November 2021, with cross-references, was executed. The main eligibility criteria were English-language articles, investigating the clinical features of olfaction and gustation in COVID-19 patients using self-rating assessment, psychophysical testing and imaging techniques. A total of 638 articles were identified and 66 were included. Self-rating assessment was performed in 31 studies, while psychophysical testing in 30 and imaging techniques in 5. The prevalence of chemosensory dysfunction was the most investigated topic, followed by the recovery time. About the psychophysical assessment, the extended version of the Sniffin’ Sticks was used in 11 articles and the Connecticut Chemosensory Clinical Research Center test in another 11. The olfactory threshold performance was the most impacted compared to the discrimination and identification capacities in accordance with the hypothesis of a tropism of SARS-CoV-2 for the olfactory mucosa. The timing significantly influenced the results of the psychophysical testing with 20% of patients presenting olfactory dysfunction at one month after infection.

Pathogenesis of Olfactory Disorders in COVID-19

Since the outbreak of the SARS-CoV-2 pandemic, olfactory disorders have been reported as a frequent symptom of COVID-19; however, its pathogenesis is still debated. The aim of this review is to summarize the current understanding of the pathogenesis of smell impairment in the course of COVID-19 and to highlight potential avenues for future research on this issue. Several theories have been proposed to explain the pathogenesis of COVID-19-related anosmia, including nasal obstruction and rhinorrhea, oedema of the olfactory cleft mucosa, olfactory epithelial damage either within the olfactory receptor cells or the supporting non-neural cells (either direct or immune-mediated), damage to the olfactory bulb, and impairment of the central olfactory pathways. Although the pathogenesis of COVID-19-related anosmia is still not fully elucidated, it appears to be mainly due to sensorineural damage, with infection of the olfactory epithelium support cells via the ACE1 receptor and disruption of the OE caused by immense inflammatory reaction, and possibly with direct olfactory sensory neurons infection mediated by the NRP-1 receptor. Involvement of the higher olfactory pathways and a conductive component of olfactory disorders, as well as genetic factors, may also be considered.

Persistent post-discharge symptoms after COVID-19 in rheumatic and musculoskeletal diseases

Objectives

We aimed to describe persistent symptoms and sequelae in patients with rheumatic and musculoskeletal diseases (RMD) after admission due to Covid-19, assessing the role of autoimmune rheumatic diseases (ARD) compared with and non-autoimmune rheumatic and musculoskeletal diseases (NARD) on persistent symptoms and sequelae.

Methods

We performed an observational study including RMD patients who attended a rheumatology clinic in Madrid that required admission due to Covid-19 (March to May 2020) and survived. The study began at discharge and ran until October 2020. Main outcomes were persistence of symptoms and sequelae related to Covid-19. The independent variable was the RMD group (ARD and NARD). Covariates included sociodemographics, clinical and treatment data. We ran a multivariate logistic regression model to assess the risk of the main outcomes by RMD group.

Results

We included 105 patients, of whom 51.5% had ARD and 68.57% reported at least 1 persistent symptom. Most frequent were dyspnea, fatigue, and chest pain. Sequelae were recorded in 31 patients. These included lung damage in 10.4% of patients, lymphopenia in 10%, a central retinal vein occlusion, and an optic neuritis. Two patients died. Eleven patients required readmission owing to Covid-19 problems (16.7% ARD vs 3.9% NARD; p = 0.053). No statistically significant differences were found between RMD groups in the final models.

Conclusions

Many RMD patients have persistent symptoms, as in other populations. Lung damage is the most frequent sequela. ARD compared with NARD does not seem to differ in terms of persistent symptoms or consequences, although ARD might have more readmissions due to Covid-19.

Recovery of olfactory and gustatory dysfunctions in coronavirus disease 2019 patients: a prospective cohort study

OBJECTIVE

This study aimed to determine the association of some demographic and clinical factors with recovery from olfactory and gustatory dysfunction in coronavirus disease 2019 patients in Iran.

METHODS

This prospective cohort study was performed on 242 coronavirus disease 2019 patients with olfactory and gustatory dysfunction. The time from onset to recovery for olfactory and gustatory dysfunction was estimated by the Kaplan-Meier estimator.

RESULTS

After six months, 239 patients (98.8 per cent) had completely recovered from olfactory dysfunction. Olfactory and gustatory dysfunction symptoms resolved in 80.99 per cent and 83.56 per cent of the patients, respectively, within the first 30 days of symptom onset. Mean recovery time for olfactory dysfunction (35.07 ± 4.25 days) was significantly longer in those infected during the first epidemic wave compared with those infected during the second wave (21.65 ± 2.05 days) (p = 0.004). A similar pattern in recovery time was observed for cases of gustatory dysfunction (p = 0.005).

CONCLUSION

The recovery rate for coronavirus disease 2019 related olfactory and gustatory dysfunction is high within the first month of symptom onset.

A German AWMF's S2e/realist synthesis and meta-narrative snapshot of craniomaxillofacial manifestations in COVID-19 patients: Rapid living update on 1 January 2021

PURPOSES

To execute a review answering the following question: "Among novel coronavirus disease (COVID19) patients, what are craniomaxillofacial (CMF) manifestations?" based on the RAMESES and the German Association of Scientific Medical Societies (AWMF)'s S2e guidelines.

METHODS

We performed a realist synthesis and meta-narrative review extracting data in English, French, German and Thai from PubMed/Medline, Embase, Biomed Central, Cochrane Library, and Thai Journals Online, until 1 January 2021. The primary outcome variable was CMF manifestations grouped into 5 categories: (1) mouth and throat, (2) nose, paranasal sinus, and skull base (3) ocular/orbital and periorbital tissue, (4) ear, and (5) craniofacial skin. Appropriate statistics was computed.

RESULTS

Thirty-seven original articles meeting the inclusion criteria were analysed; all were in English and indexed in PubMed/Medline. Hand searches of their references yielded a total of 101 articles for the review. Most data were in low level of evidence and focused on smell and taste disturbances and non-specific orofacial lesions. Iatrogenic complications may occur in this body region. Conservative measures remained effective and were usually enough for patient care.

CONCLUSION

Because SARS-CoV-2 infection is new and becomes the stringent worldwide pandemic within a short time period, most of the data on CMF symptoms are of low level evidence. Apart from taste and smell dysfunctions, non-specific CMF lesions can be found and treated conservatively. Treatment complications are possible. Dentists and CMF surgeons are privileged to examine the orofacial region and work closely with colleagues in other specialities to combat this pandemic.

Prevalence of olfactory dysfunction and quality of life in hospitalised patients 1 year after SARS-CoV-2 infection: a cohort study

OBJECTIVES

To determine the long-term prevalence of olfactory and/or gustatory dysfunction (OD±GD), associated risk factors and impact on quality of life (QoL) in previously hospitalised patients with COVID-19 1 year after infection.

DESIGN

A single-centre cohort study.

SETTING

Patients admitted at a large central London hospital with COVID-19 infection between 10 February 2020 and 22 May 2020.

PARTICIPANTS

150 adult subjects with previously confirmed SARS-CoV-2 infection were recruited between 10 December 2020 and 29 January 2021. Participants were predominantly male (102/150, 68.0%); mean age 58.0±15.9 years and 41.2% (56/136) were of black, Asian and minority ethnic backgrounds.

MAIN OUTCOME MEASURES

EQ-5D-5L values and Sino-Nasal Outcome Test-22 (SNOT-22) scores.

RESULTS

Long-term prevalence of OD±GD was 12.8% (19/149) at median time of 264.5 days following SARS-CoV-2 infection onset. Patients with OD±GD had a significantly higher median total SNOT-22 score (46.1; Q1-Q3: 23.0-60.0; 95% CI 23.0 to 60.0) compared with those without (16.0; Q1-Q3: 5.0-30.5; 95% CI 12.0 to 18.0) (p=0.0002), reflecting poorer QoL, particularly psychological well-being (p=0.0004), which was not alleviated with time (p=0.4977). Median EQ-5D-5L value was not significantly different between patients with OD±GD (0.70; Q1-Q3: 0.38-0.83; 95% CI 0.38 to 0.83) and those without (0.83; Q1-Q3: 0.61-0.94; 95% CI 0.75 to 0.89) (p=0.0627). Age, sex, ethnicity, smoking status, highest C reactive protein value, intubation and ventilation, and oxygen supplementation were not found to influence OD±GD (p>0.05).

CONCLUSIONS

12.8% of previously hospitalised patients with COVID-19 in London still report persistent problems with smell or taste up to a year after infection, impacting their QoL. Increased holistic support including psychological therapy and olfactory rehabilitation for affected patients may help to reduce long-term morbidity.

Self-reported olfactory and gustatory dysfunctions in COVID-19 patients: a 1-year follow-up study in Foggia district, Italy

BACKGROUND

From the initial stages of the pandemic in early 2020, COVID-19-related olfactory and gustatory dysfunctions have been widely reported and are emerging as one of the most frequent long-term sequelae of SARS-CoV-2 infection. However, data regarding the long-term recovery of the sense of smell and taste are lacking. This study aimed to characterize the evolution up to one year after the diagnosis of self-reported olfactory and gustatory dysfunctions in COVID-19 cases.

METHODS

Based on the data of the active surveillance platform of the Apulia region, Italy, we selected the residents of Foggia district who were confirmed positive for SARS-CoV-2 from March 1st to June 16th, 2020, and home-quarantined with paucisymptomatic-to-mild clinical presentation. Self-reported olfactory and gustatory dysfunctions were recorded at baseline through a survey of dichotomous questions. The evolution of these symptoms at approximately one year was prospectively assessed via telephone by the validated sino-nasal outcome test 22 (SNOT-22, Italian version).

RESULTS

Among the 1,175 COVID-19 cases notified in the Foggia district during the first epidemic wave, 488 had paucisymptomatic-to-mild clinical presentation. Of these, 41.2% (n = 201, 95% confidence interval [CI] 36.8-45.7%) reported at least one sensory dysfunction. A total of 178 to 201 (88.5%) patients agreed to participate in the follow-up survey. According to the SNOT-22 results, the persistence of a sensory dysfunction was observed in the 29.8% (n = 53, 95% CI 23.2-37.1%) of them. Particularly, loss of smell persisted in 25.8% (n = 46, 95% CI 19.6-32.9%), loss of taste in 21.3% (n = 38, 95% CI 15.6-28.1%), loss of both in 17.4% (n = 31, 95% CI 12.2-23.8%) of participants in the follow-up. The rates of full recovery increased over time: from 59% at 30 days to 71.9% at 90 days for the sense of smell; from 61.3% at 30 days to 74.7% at 90 days for the sense of taste.

CONCLUSIONS

The persistence of COVID-19-related olfactory and gustatory dysfunctions up to 12 months after the disease onset in a noteworthy proportion (approximately 3 out of 10) of patients with paucisymptomatic-to-mild clinical presentation deserves further investigations due to its possible pathophysiological implications and impact on the quality of life.

Taste loss as a distinct symptom of COVID-19: a systematic review and meta-analysis

Chemosensory scientists have been skeptical that reports of COVID-19 taste loss are genuine, in part because before COVID-19 taste loss was rare and often confused with smell loss. Therefore, to establish the predicted prevalence rate of taste loss in COVID-19 patients, we conducted a systematic review and meta-analysis of 376 papers published in 2020-2021, with 241 meeting all inclusion criteria. Drawing on previous studies and guided by early meta-analyses, we explored how methodological differences (direct vs. self-report measures) may affect these estimates. We hypothesized that direct measures of taste are at least as sensitive as those obtained by self-report and that the preponderance of evidence confirms taste loss is a symptom of COVID-19. The meta-analysis showed that, among 138,897 COVID-19-positive patients, 39.2% reported taste dysfunction (95% confidence interval: 35.34%-43.12%), and the prevalence estimates were slightly but not significantly higher from studies using direct (n = 18) versus self-report (n = 223) methodologies (Q = 0.57, df = 1, P = 0.45). Generally, males reported lower rates of taste loss than did females, and taste loss was highest among middle-aged adults. Thus, taste loss is likely a bona fide symptom of COVID-19, meriting further research into the most appropriate direct methods to measure it and its underlying mechanisms.

Clinical, virological and immunological evolution of the olfactory and gustatory dysfunction in COVID-19

PURPOSE

New-onset olfactory and gustatory dysfunction (OGD) represents a well-acknowledged COVID-19 red flag. Nevertheless, its clinical, virological and serological features are still a matter of debate.

MATERIALS AND METHODS

For this cohort study, 170 consecutive subjects with new-onset OGD were consecutively recruited. Otolaryngological examination, OGD subjective grading, nasopharyngeal swabs (NS) for SARS-CoV-2 RNA detection and serum samples (SS) collection for SARS-CoV-2 IgG quantification were conducted at baseline and after one (T1), two (T2) and four weeks (T3).

RESULTS

SARS-CoV-2 infection was confirmed in 79% of patients. Specifically, 43% of positive patients were detected only by SS analysis. The OGD was the only clinical complaint in 10% of cases. Concurrent sinonasal symptoms were reported by 45% of patients. Subjective improvement at T3 was reported by 97% of patients, with 40% recovering completely. Hormonal disorders and RNA detectability in NS were the only variables associated with OGD severity. Recovery rate was higher in case of seasonal influenza vaccination, lower in patients with systemic involvement and severe OGD. Not RNA levels nor IgG titers were correlated with recovery.

CONCLUSION

Clinical, virological and serological features of COVID-19 related OGD were monitored longitudinally, offering valuable hints for future research on the relationship between host characteristics and chemosensory dysfunctions.

Vitamin A in resistance to and recovery from infection: relevance to SARS-CoV2

SARS-CoV2 infects respiratory epithelial cells via its cellular receptor angiotensin-converting enzyme 2, causing a viral pneumonia with pronounced inflammation resulting in significant damage to the lungs and other organ systems, including the kidneys, though symptoms and disease severity are quite variable depending on the intensity of exposure and presence of underlying conditions that may affect the immune response. The resulting disease, coronavirus disease 2019 (COVID-19), can cause multi-organ system dysfunction in patients requiring hospitalisation and intensive care treatment. Serious infections like COVID-19 often negatively affect nutritional status, and the resulting nutritional deficiencies may increase disease severity and impair recovery. One example is the viral infection measles, where associated vitamin A (VA) deficiency increases disease severity and appropriately timed supplementation during recovery reduces mortality and hastens recovery. VA may play a similar role in COVID-19. First, VA is important in maintaining innate and adaptive immunity to promote clearance of a primary infection as well as minimise risks from secondary infections. Second, VA plays a unique role in the respiratory tract, minimising damaging inflammation, supporting repair of respiratory epithelium and preventing fibrosis. Third, VA deficiency may develop during COVID-19 due to specific effects on lung and liver stores caused by inflammation and impaired kidney function, suggesting that supplements may be needed to restore adequate status. Fourth, VA supplementation may counteract adverse effects of SARS-CoV2 on the angiotensin system as well as minimises adverse effects of some COVID-19 therapies. Evaluating interactions of SARS-CoV2 infection with VA metabolism may thus provide improved COVID-19 therapy.

[Understanding and caring for patients with smelly wounds]

Sudden loss of smell is a very common symptom that can be observed in two-thirds of patients with Covid-19, and may be the only symptom of this disease. A study has demonstrated that 80% of infected patients have sudden loss of smell without nasal obstruction. This suggests that anomalies of the olfactory epithelium are a key element of pathogenesis and local involvement. Management of odor disorders related to Covid-19 is still being debated. Share of experience of the ear, nose and throat team at the University Hospital of Nancy (54).

Olfactory recovery following infection with COVID-19: A systematic review

Olfactory loss has been identified as one of the common symptoms related to COVID-19 infection. Although olfactory loss is recognized, our understanding of both the extent of loss and time to olfactory recovery following infection is less well known. Similarly, knowledge of potential impactful patient factors and therapies that influence olfactory recovery is desirable but is not overtly clear in the literature. Our systematic review sought to fill this knowledge gap. We included studies that: involved either an observational or an interventional design that reported data on patients with olfactory dysfunction due to Reverse Transcription Polymerase Chain Reaction (RT-PCR) diagnosed COVID-19 infection; and reported data regarding olfactory recovery measured by an objective olfactory test, Likert scale and/or visual analog scale (VAS). The study methods were determined a priori and registered in PROSPERO (Registration Number CRD42020204354). An information specialist searched Medline, Embase, LitCovid and the Cochrane Register of Controlled Trials up to March 2021, and two reviewers were involved in all aspects of study selection and data collection. After screening 2788 citations, a total of 44 studies of assorted observational designs were included. Patients had undergone objective COVID-19 testing, and most were adult patients with mild to moderate COVID-19. Olfactory recovery was found to occur as early as 7 days, with most patients recovering olfaction within 30 days. Few studies included prolonged follow-up to 6 months or longer duration. Poor olfaction at initial presentation was associated with poor recovery rates. Only a small number of studies assessed olfactory retraining and steroid therapy. Additional trials are underway.

Taste loss as a distinct symptom of COVID-19: A systematic review and meta-analysis

Chemosensory scientists have been skeptical that reports of COVID-19 taste loss are genuine, in part because before COVID-19, taste loss was rare and often confused with smell loss. Therefore, to establish the predicted prevalence rate of taste loss in COVID-19 patients, we conducted a systematic review and meta-analysis of 376 papers published in 2020-2021, with 241 meeting all inclusion criteria. Additionally, we explored how methodological differences (direct vs. self-report measures) may affect these estimates. We hypothesized that direct prevalence measures of taste loss would be the most valid because they avoid the taste/smell confusion of self-report. The meta-analysis showed that, among 138,897 COVID-19-positive patients, 39.2% reported taste dysfunction (95% CI: 35.34-43.12%), and the prevalence estimates were slightly but not significantly higher from studies using direct (n = 18) versus self-report (n = 223) methodologies (Q = 0.57, df = 1, p = 0.45). Generally, males reported lower rates of taste loss than did females and taste loss was highest in middle-aged groups. Thus, taste loss is a bona fide symptom COVID-19, meriting further research into the most appropriate direct methods to measure it and its underlying mechanisms.

COVID-19 related olfactory dysfunction prevalence and natural history in ambulatory patients

Background

Evidence regarding prevalence of COVID-19 related Olfactory dysfunction (OD) among ambulatory patients is highly variable due to heterogeneity in study population and measurement methods. Relatively few studies have longitudinally investigated OD in ambulatory patients with objective methods.

Methods

We performed a longitudinal study to investigate OD among COVID-19 ambulatory patients compared to symptomatic controls who test negative. Out of 81 patients enrolled, 45 COVID-19 positive patients and an age- and sex-matched symptomatic control group completed the BSIT and a questionnaire about smell, taste and nasal symptoms. These were repeated at 1 month for all COVID-19 positive patients, and again at 3 months for those who exhibited persistent OD. Analysis was performed by mixed-effects linear and logistic regression.

Results

46.7% of COVID-19 patients compared to 3.8% of symptomatic controls exhibited OD at 1-week post diagnosis (p<0.001). At 1 month, 16.7%, (6 of 36), of COVID-19 patients had persistent OD. Mean improvement in BSIT score in COVID-19 patients between 1-week BSIT and 1 month follow-up was 2.0 (95% CI 1.00 - 3.00, p<0.001). OD did not correlate with nasal congestion (r= -0.25, 95% CI, -0.52 to 0.06, p=0.12).

Conclusions

Ambulatory COVID-19 patients exhibited OD significantly more frequently than symptomatic controls. Most patients regained normal olfaction by 1 month. The BSIT is a simple validated and objective test to investigate the prevalence of OD in ambulatory patients. OD did not correlate with nasal congestion which suggests a congestion-independent mechanism of OD.

Neurological Manifestations in COVID-19 Patients: A Meta-Analysis

Common symptoms such as dizziness, headache, olfactory dysfunction, nausea, vomiting, etc. in COVID-19 patients have indicated the involvement of the nervous system. However, the exact association of the nervous system with COVID-19 infection is still unclear. Thus, we have conducted a meta-analysis of clinical studies associated with neurological problems in COVID-19 patients. We have searched for electronic databases with MeSH terms, and the studies for analysis were selected based on inclusion and exclusion criteria and quality assessment. The Stats Direct (version 3) was used for the analysis. The pooled prevalence with 95% confidence interval of various neurological manifestations reported in the COVID-19 patients was found to be headache 14.6% (12.2-17.2), fatigue 33.6% (29.5-37.8), olfactory dysfunction 26.4% (21.8-31.3), gustatory dysfunction 27.2% (22.3-32.3), vomiting 6.7% (5.5-8.0), nausea 9.8% (8.1-11.7), dizziness 6.7% (4.7-9.1), myalgia 21.4% (18.8-24.1), seizure 4.05% (2.5-5.8), cerebrovascular diseases 9.9% (6.8-13.4), sleep disorders 14.9% (1.9-36.8), altered mental status 17.1% (12.3-22.5), neuralgia 2.4% (0.8-4.7), arthralgia 19.9% (15.3-25.0), encephalopathy 23.5% (14.3-34.1), encephalitis 0.6% (0.2-1.3), malaise 38.3% (24.7-52.9), confusion 14.2% (6.9-23.5), movement disorders 5.2% (1.7-10.4), and Guillain-Barre syndrome 6.9% (2.3-13.7). However, the heterogeneity among studies was found to be high. Various neurological manifestations related to the central nervous system (CNS) and peripheral nervous system (PNS) are associated with COVID-19 patients.

Clinical significance of olfactory dysfunction in patients of COVID-19

BACKGROUND

Currently, as the coronavirus disease (COVID-19) has become a pandemic, rapidly obtaining accurate information of patient symptoms and their progression is crucial and vital. Although the early studies in China have illustrated that the representative symptoms of COVID-19 include (dry) cough, fever, headache, fatigue, gastrointestinal discomfort, dyspnea, and muscle pain, there is increasing evidence to suggest that olfactory and taste disorder are related to the COVID-19 pandemic. Therefore, we conduct this study to review the present literature about the correlation between anosmia or dysgeusia and COVID-19.

METHODS

A comprehensive literature search in 2020 of the electronic journal databases, mainly PubMed or Web of Science, was performed using the keywords COVID-19 or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with hyposmia, anosmia, dysgeusia, olfactory disorder, or olfactory dysfunction. The country, study period, case number, inpatient or outpatient medical visit, evaluation method (subjective complaints of dysfunction or objective evaluation), and occurrence rate of olfactory or gustatory function were reviewed.

RESULTS

Many studies reported that the recoverable olfactory or gustatory dysfunction may play an important role as the early clinical symptom of COVID-19. It is associated with better prognosis, although further investigation and validation should be carried out.

CONCLUSION

Studies have shown that smell and taste disturbances may represent an early symptom of COVID-19 and healthcare professionals must be very vigilant when managing patients with these symptoms. In the pandemic era, this implies testing for COVID-19 by healthcare workers with full personal protective equipment.

The outcome of olfactory impairment in patients with otherwise paucisymptomatic coronavirus disease 2019 during the pandemic

OBJECTIVE

This study aimed to measure the duration and recovery rate of olfactory loss in patients complaining of recent smell loss as their prominent symptom during the coronavirus disease 2019 outbreak.

METHOD

This was a prospective telephone follow-up observational study of 243 participants who completed an online survey that started on 12 March 2020.

RESULTS

After a mean of 5.5 months from the loss of smell onset, 98.3 per cent of participants reported improvement with a 71.2 per cent complete recovery rate after a median of 21 days. The chance of complete recovery significantly decreased after 131 days from the onset of loss of smell (100 per cent sensitive and 97.7 per cent specific). Younger age and isolated smell loss were associated with a rapid recovery, whereas accompanying rhinological and gastrointestinal symptoms were associated with longer loss of smell duration.

CONCLUSION

Smell loss, occurring as a prominent symptom during the coronavirus disease 2019 pandemic, showed a favourable outcome. However, after 5.5 months from the onset, around 10 per cent of participants still complained of moderate or severe hyposmia.

Long Covid-19: Proposed Primary Care Clinical Guidelines for Diagnosis and Disease Management

Long COVID-19 may be defined as patients who, four weeks after the diagnosis of SARS-Cov-2 infection, continue to have signs and symptoms not explainable by other causes. The estimated frequency is around 10% and signs and symptoms may last for months. The main long-term manifestations observed in other coronaviruses (Severe Acute Respiratory Syndrome (SARS), Middle East respiratory syndrome (MERS)) are very similar to and have clear clinical parallels with SARS-CoV-2: mainly respiratory, musculoskeletal, and neuropsychiatric. The growing number of patients worldwide will have an impact on health systems. Therefore, the main objective of these clinical practice guidelines is to identify patients with signs and symptoms of long COVID-19 in primary care through a protocolized diagnostic process that studies possible etiologies and establishes an accurate differential diagnosis. The guidelines have been developed pragmatically by compiling the few studies published so far on long COVID-19, editorials and expert opinions, press releases, and the authors' clinical experience. Patients with long COVID-19 should be managed using structured primary care visits based on the time from diagnosis of SARS-CoV-2 infection. Based on the current limited evidence, disease management of long COVID-19 signs and symptoms will require a holistic, longitudinal follow up in primary care, multidisciplinary rehabilitation services, and the empowerment of affected patient groups.

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.

Loss of smell and taste in COVID-19 infection in adolescents

OBJECTIVES

To study the prevalence, clinical course and outcomes of olfactory and taste dysfunction in COVID-19 positive adolescents.

METHODS

This prospective study was carried out from May to August 2020. The adolescents, aged 10-19 years, who were detected COVID-19 positive by RT-PCR with mild to moderate disease were included in the study. The following epidemiological and clinical outcomes were studied: age, sex, general symptoms, olfactory and taste dysfunction.

RESULTS

Out of 141 patients included in the study, there were 83 males (58.9%) and 58 females (41.1%). The age varied from 10 to 19 years with an average of 15.2 years. Forty patients (28.4%) had olfactory or taste dysfunction. Out of these 40 patients, 28 patients (19.8%) had both olfactory and taste dysfunction. Of the 34 patients (24.1%) who complained of olfactory dysfunction, 16 patients complained of hyposmia and 18 patients complained of anosmia. Dysgeusia was reported by 34 patients (24.1%). The duration of OTD varied from 2 to 15 days with an average of 5.7 days.

CONCLUSION

Loss of smell and taste are common symptoms in COVID-19 positive adolescents. It recovers spontaneously within a few weeks, along with the resolution of other symptoms.

Onset, duration and unresolved symptoms, including smell and taste changes, in mild COVID-19 infection: a cohort study in Israeli patients

OBJECTIVES

To characterize longitudinal symptoms of mild coronavirus disease 2019 (COVID-19) patients for a period of 6 months, to potentially aid in disease management.

METHODS

Phone interviews were conducted with 103 patients with mild COVID-19 in Israel over a 6-month period (April 2020 to October 2020). Patients were recruited via social media and word to mouth and were interviewed up to 4 times, depending on reports of their unresolved symptoms. Inclusion criteria required participants to be residents of Israel aged 18 years or older, with positive COVID-19 real-time PCR results and nonsevere symptoms. The onset, duration, severity and resolution of symptoms were analysed.

RESULTS

A total of 44% (45/103), 41% (42/103), 39% (40/103) and 38% (39/103) of patients experienced headache, fever, muscle ache and dry cough as the first symptom respectively. Smell and taste changes were experienced at 3.9 ± 5.4 and 4.6 ± 5.7 days (mean ± standard deviation (SD)) after disease onset respectively. Among prevalent symptoms, fever had the shortest duration (5.8 ± 8.6 days), and taste and smell changes were the longest-lasting symptoms (17.2 ± 17.6 and 18.9 ± 19.7 days; durations censored at 60 days). Longer recovery of the sense of smell correlated with the extent of smell change. At the 6-month follow-up, 46% (47/103) of the patients had at least one unresolved symptom, most commonly fatigue (22%, 23/103), smell and taste changes (15%, 15/103 and 8%, 8/103 respectively) and breathing difficulties (8%, 8/103).

CONCLUSIONS

Long-lasting effects of mild COVID-19 manifested in almost half of the participants reporting at least one unresolved symptom after 6 months.

The prognostic role of IL-10 in non-severe COVID-19 with chemosensory dysfunction

Objectives

Olfactory and gustatory dysfunction (OD/GD) are now recognized as typical symptoms of COVID-19 infection. However, their pathogenesis remains unclear and no clear prognostic factors have been identified. We have analyzed a cohort of mild/moderate hospitalized patients to identify possible clinical or immunological predictors of recovery from OD/GD.

Methods

Clinical and biological parameters were reviewed along with associated comorbidities. Chemosensory Complaint Score was administered on admission and 30 days after the first negative swab. Unpaired Wilcoxon and chi-squared tests were used to compare the variables in the patients who recovered versus those who did not.

Results

From a cohort of 119 hospitalized patients, 43 (36%) reported OD/GD on admission. 60.6% had a full recovery from OD and 69.2% from GD. Only the concentration of IL-10 on admission emerged as significantly associated with recovery of taste (p = 0.041) while allergic respiratory disease was more prevalent in the group who did not recover from OD (p = 0.049) and GD (p = 0.007).

Conclusion

These findings suggest that COVID-19 associated OD/GD is an inflammatory-mediated condition and that clinical and immunological parameters could predict the evolution of these symptoms.

The coronavirus disease 2019: the prevalence, prognosis, and recovery from olfactory dysfunction (OD)

BACKGROUND

Many patients with coronavirus disease 2019 (COVID-19) complain from olfactory dysfunction (OD). Aims/objectives: To evaluate the prevalence, prognosis, and recovery from OD in COVID-19 patients.

MATERIAL AND METHODS

In this study, patients with COVID-19 symptoms who were referred to six different tertiary referral centres were recruited after positive results for COVID-19. All patients were assessed for a one-month follow-up after the initial diagnosis of COVID-19.

RESULTS

Three hundred and eleven patients with COVID-19 were recruited in the present study. Two hundred and seven patients (66.6%) had a recent history of OD. One hundred and seventy-eight patients had experienced OD as a primary symptom intercurrent to other COVID-19 symptoms or solely. Sixty-nine patients had OD at the time of presentation to referral centres. Headache and nasal obstruction had significant relationships with recovery from OD in this subgroup, and the platelet count was the most important predictor for the recovery from OD. One hundred seventy-nine (86.4%) patients were nearly or fully recovered from OD approximately a month after the onset of OD.

CONCLUSION

Headache, nasal obstruction, and platelet count may have specific roles as prognostic factors in the recovery from OD.

The Association of "Loss of Smell" to COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

The presence of olfactory dysfunction or "loss of smell" has been reported as an atypical symptom in patients with coronavirus disease 2019 (COVID-19). We performed a systematic review and meta-analysis of the available literature to evaluate the prevalence of "loss of smell" in COVID-19 as well as its utility for prognosticating the disease severity.

METHODS

An exhaustive search of the PubMed/Medline, Embase, Web of Science, Cochrane Library, LitCovid NIH, and WHO COVID-19 database was conducted through August 6th, 2020. All studies reporting the prevalence of "loss of smell" (anosmia and/or hyposmia/microsmia) in laboratory-confirmed COVID-19 patients were included. Pooled prevalence for cases (positive COVID-19 through reverse transcriptase (RT-PCR) and/or serology IgG/IgM) and controls (negative RT-PCR and/or serology) was compared, and the odds ratio (OR), 95% confidence interval (CI) and the p-value were calculated. A p-value of <0.05 was considered statistically significant.

RESULTS

A total of 51 studies with 11074 confirmed COVID-19 patients were included. Of these, 21 studies used a control group with 3425 patients. The symptom of "loss of smell" (OR: 14.7, CI: 8.9-24.3) was significantly higher in the COVID-19 group when compared to the control group. Seven studies comparing severe COVID-19 patients with- and without "loss of smell" demonstrated favorable prognosis for patients with "loss of smell" (OR: 0.36, CI 0.27-0.48).

CONCLUSIONS

Olfactory dysfunction or "loss of smell" is a prevalent symptom in COVID-19 patients. Moreover, COVID-19 patients with "loss of smell" appear to have a milder course of the disease.

Anosmia and dysgeusia in SARS-CoV-2 infection: incidence and effects on COVID-19 severity and mortality, and the possible pathobiology mechanisms - a systematic review and meta-analysis

Background: The present study aimed to determine the global prevalence of anosmia and dysgeusia in coronavirus disease 2019 (COVID-19) patients and to assess their association with severity and mortality of COVID-19. Moreover, this study aimed to discuss the possible pathobiological mechanisms of anosmia and dysgeusia in COVID-19. Methods: Available articles from PubMed, Scopus, Web of Science, and preprint databases (MedRxiv, BioRxiv, and Researchsquare) were searched on November 10th, 2020. Data on the characteristics of the study (anosmia, dysgeusia, and COVID-19) were extracted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Newcastle-Ottawa scale was used to assess research quality. Moreover, the pooled prevalence of anosmia and dysgeusia were calculated, and the association between anosmia and dysgeusia in presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was assessed using the Z test. Results: Out of 32,142 COVID-19 patients from 107 studies, anosmia was reported in 12,038 patients with a prevalence of 38.2% (95% CI: 36.5%, 47.2%); whereas, dysgeusia was reported in 11,337 patients out of 30,901 COVID-19 patients from 101 studies, with prevalence of 36.6% (95% CI: 35.2%, 45.2%), worldwide. Furthermore, the prevalence of anosmia was 10.2-fold higher (OR: 10.21; 95% CI: 6.53, 15.96, p < 0.001) and that of dysgeusia was 8.6-fold higher (OR: 8.61; 95% CI: 5.26, 14.11, p < 0.001) in COVID-19 patients compared to those with other respiratory infections or COVID-19 like illness. To date, no study has assessed the association of anosmia and dysgeusia with severity and mortality of COVID-19. Conclusion: Anosmia and dysgeusia are prevalent in COVID-19 patients compared to those with the other non-COVID-19 respiratory infections. Several possible mechanisms have been hypothesized; however, future studies are warranted to elucidate the definitive mechanisms of anosmia and dysgeusia in COVID-19. Protocol registration: PROSPERO CRD42020223204.

Using Anti-SARS-CoV-2 IgG and IgM Antibodies to Detect Outpatient Cases with Olfactory and Taste Disorders Suspected as Mild Form of COVID-19: a Retrospective Survey

Many patients with olfactory disorders were referred during the COVID-19 pandemic in 2020. The aim of this study was to detect outpatient cases with olfactory and taste disorders suspected to mild form of COVID-19 disease in Gorgan city in the north of Iran retrospectively. This study was performed on patients who had the complaints of olfactory disorders during 03/01/2020 to 04/01/2020. They also had the mild symptoms of upper respiratory tract infection. The control group included patients who had similar symptoms during this period but did not report olfactory or taste disturbances. Due to the limitations of serologic kits, this study was performed 2-3 months after the onset of symptoms. The number of patients and controls was 72 and 36 respectively. The range and the mean ± SD of patient's age were 21-63 and 39.82 ± 9.82 years. In both groups, 44.44% were male and 55.56% were female. The time interval between the onset of symptoms and the serologic tests in both groups was 91.11 ± 16.20 days. In the cases and controls, the IgG titer was positive in 44.4% and 22.2% and the IgM titer was positive in 5.6% and 8.3% respectively. IgG antibody titers were higher in cases than in the control group (P = 0.024). There was no correlation among antibody titers and the severity of olfactory disturbances, the gender, and the age. The high COVID-19 IgG antibody titer in patients with olfactory disorder during the pandemic can probably be considered as a warning complaint of COVID-19 and may be used for isolation plans.

Using Anti-SARS-CoV-2 IgG and IgM Antibodies to Detect Outpatient Cases with Olfactory and Taste Disorders Suspected as Mild Form of COVID-19: a Retrospective Survey

Many patients with olfactory disorders were referred during the COVID-19 pandemic in 2020. The aim of this study was to detect outpatient cases with olfactory and taste disorders suspected to mild form of COVID-19 disease in Gorgan city in the north of Iran retrospectively. This study was performed on patients who had the complaints of olfactory disorders during 03/01/2020 to 04/01/2020. They also had the mild symptoms of upper respiratory tract infection. The control group included patients who had similar symptoms during this period but did not report olfactory or taste disturbances. Due to the limitations of serologic kits, this study was performed 2–3 months after the onset of symptoms. The number of patients and controls was 72 and 36 respectively. The range and the mean ± SD of patient’s age were 21–63 and 39.82 ± 9.82 years. In both groups, 44.44% were male and 55.56% were female. The time interval between the onset of symptoms and the serologic tests in both groups was 91.11 ± 16.20 days. In the cases and controls, the IgG titer was positive in 44.4% and 22.2% and the IgM titer was positive in 5.6% and 8.3% respectively. IgG antibody titers were higher in cases than in the control group (P = 0.024). There was no correlation among antibody titers and the severity of olfactory disturbances, the gender, and the age. The high COVID-19 IgG antibody titer in patients with olfactory disorder during the pandemic can probably be considered as a warning complaint of COVID-19 and may be used for isolation plans.

COVID-19 in hemodialysis patients in Colombia: Report of seven cases

A finales del 2019 se inició en Wuhan, China, el brote de un nuevo coronavirus que se dispersó por todo el mundo infectando y cobrando miles de vidas. Se ha encontrado que ciertas comorbilidades constituyen factores de riesgo para resultados poco satisfactorios de la enfermedad, pero es poco lo que se ha descrito sobre pacientes en hemodiálisis, a pesar de tratarse de una población de alto riesgo de infección, complicaciones y muerte. En este artículo se describe el curso clínico, las manifestaciones clínicas y las complicaciones de la COVID-19 en siete pacientes en hemodiálisis permanente y se hacen recomendaciones para el manejo de pacientes con enfermedad renal crónica.