The diagnostic value of detecting sudden smell loss among asymptomatic COVID-19 patients in early stage: The possible early sign of COVID-19

Using SCENTinel® to predict SARS-CoV-2 infection: insights from a community sample during dominance of Delta and Omicron variants

Introduction

Based on a large body of previous research suggesting that smell loss was a predictor of COVID-19, we investigated the ability of SCENTinel®, a newly validated rapid olfactory test that assesses odor detection, intensity, and identification, to predict SARS-CoV-2 infection in a community sample.

Methods

Between April 5, 2021, and July 5, 2022, 1,979 individuals took one SCENTinel® test, completed at least one physician-ordered SARS-CoV-2 PCR test, and endorsed a list of self-reported symptoms.

Results

Among the of SCENTinel® subtests, the self-rated odor intensity score, especially when dichotomized using a previously established threshold, was the strongest predictor of SARS-CoV-2 infection. SCENTinel® had high specificity and negative predictive value, indicating that those who passed SCENTinel® likely did not have a SARS-CoV-2 infection. Predictability of the SCENTinel® performance was stronger when the SARS-CoV-2 Delta variant was dominant rather than when the SARS-CoV-2 Omicron variant was dominant. Additionally, SCENTinel® predicted SARS-CoV-2 positivity better than using a self-reported symptom checklist alone.

Discussion

These results indicate that SCENTinel® is a rapid assessment tool that can be used for population-level screening to monitor abrupt changes in olfactory function, and to evaluate spread of viral infections like SARS-CoV-2 that often have smell loss as a symptom.

The prevalence of symptoms and its correlation with sex in polish COVID-19 adult patients: Cross-sectional online open survey

Background

The understanding and treatment of COVID-19 has improved rapidly since December 2019 when SARS-CoV-2 was sequenced. However most papers on its symptomatology focus on hospitalized patients and address only a limited number of major presentations. Although differences depending on sex of COVID-19 patients have been previously confirmed (higher ICU admission and higher death rate for men), no publication has focused on sex-related differences in COVID-19 symptomatology.

Objective

The aim of the study was to present a reliable list of COVID-19 symptoms and identify any differences in symptom prevalence depending on sex.

Methods

A sample of Polish patients suffering from COVID-19 were surveyed using a cross-sectional anonymous online survey in Polish available on a web-based surveying platform (Survey Monkey). The survey included 20 questions asking about COVID-19 symptoms, days of occurrence (from day 1 until day 14 and “15 days or more”) and patient characteristics including sex, age, height, weight, place of residence and type of therapy received during COVID-19. The survey was made available during the third COVID-19 wave in Poland. The link to the survey was distributed across social networks. Participation was open to anyone willing, without any incentives. The data was analyzed statistically.

Results

Survey responses were collected from 2,408 participants (56.9% women) aged 18–90 (42 ± 12), 84.7% living in cities, who took part in the study between December 2020 and February 2021. Out of 54 predefined symptoms, the three most prevalent were fatigue (reported by 87.61% respondents), anosmia (73.74%) and headache (69.89%). Women were found to be more symptomatic than men, 31 symptoms occurred more often in women (including anosmia, headache and myalgias, p < 0.05). Subfebrility, fever and hemoptysis were more prevalent in men. Twelve symptoms (incl. hypothermia, sneezing and nausea) lasted longer in women than men (p < 0.05). Fatigue, cough, nasal dryness, xerostomia and polydipsia were the longest lasting symptoms of COVID-19 (lasted over 14 days).

Conclusion

Our study presents a wide range of symptoms, which may enable better recognition of COVID-19, especially in an outpatient setting. Understanding these differences in the symptomatology of community and hospitalized patients may help diagnose and treat patients faster and more accurately. Our findings also confirmed differences in symptomatology of COVID-19 between men and women, which may lay the foundation for a better understanding of the different courses of this disease in the sexes. Further studies are necessary to understand whether a different presentation correlates with a different outcome.

The effects of comorbidities on the change of taste and smell in COVID-19 patients

Background

Sudden chemosensory changes were considered an early predictor of COVID-19. Here, the effects of comorbidities on changes in taste and smell in COVID-19 patients were investigated based on a worldwide study.

Methods

Data analyzed here were collected from the Global Consortium for Chemosensory Research (GCCR) core questionnaire, including questions regarding preexisting disease conditions. Overall, the final sample of 12,438 participants who were diagnosed with COVID-19 included patients with preexisting conditions. Mixed linear regression models were used to test our hypothesis, and the p-value of interaction was examined.

Results

A total of 61,067 participants completed the GCCR questionnaire, including 16,016 participants had preexisting diseases. The multivariate regression analysis showed that individuals with high blood pressure, lung disease, or sinus problems, or neurological diseases exhibited worse self-reported smell loss (p < .05), but no apparent significant differences in the smell or taste recovery. COVID-19 patients with seasonal allergy/hay fever lost their olfactory ability more than patients who did not have it (with 11.90 [9.67, 14.13] vs. without 6.97 [6.04, 7.91], p < .0001). The taste ability, smell loss and taste loss after COVID-19 recovery also decreased in the COVID-19 patients with seasonal allergy/hay fever (p < .001). Preexisting condition of diabetes did not worsen to chemosensory disorder but also had no obvious impact on the chemosensory recovery after acute infection. Preexisting diseases also affected the type of smell change in the COVID-19 patients with seasonal allergy/hay fever or sinus problems (p < .05).

Conclusions

COVID-19 patients with high blood pressure, lung disease, or sinus problems, or neurological diseases exhibited worse self-reported smell loss, but no differences in the smell or taste recovery. COVID-19 patients with seasonal allergy/hay fever had greater loss of smell and taste, poorer smell and taste recovery.

Level of Evidence

4.

Unmasking the 'Asymptomatic' COVID-19: A Nose Question

The new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has high infectivity, often masked by asymptomatic carriers, which allows it to spread rapidly and become a pandemic. Attempts to slow the pandemic at this stage depend on the ability to unmask asymptomatic carriers. The rapid diagnosis of active coronavirus disease 2019 (COVID-19) infection is one of the cornerstones of pandemic control, as the nasal cavity is the main gateway for SARS-CoV-2 entry and altered sense of smell is a feature of the current virus. In the present study, we therefore tested the olfactory threshold coupled with heart–lung parameters in subjects undergoing traditional molecular testing, resulting in a significantly different score between asymptomatic subjects and healthy controls. In total, 82% of asymptomatic positives showed olfactory impairment; of these, 46% had severe hyposmia and 7% had anosmia, while in the control 9% had severe hyposmia and 0% had anosmia, respectively, which agrees with heart rate, breathing rate, and blood pressure parameter variations. The olfactory test coupled with physiological parameters may help to identify asymptomatic people. In conclusion, our results suggest that most asymptomatic individuals could be unmasked by mass olfactory rapid threshold screening and then referred to traditional slower diagnostic tests.

Correlation between Post-COVID-19, Chemosensitive Function, Blood Group, and Oral Health-Related Quality of Life

Materials and Methods

A cross-sectional information on demographics, symptomatic disease status, ABO blood group, and oral health-related quality of life (OHRQoL) was collected among 100 patients who were earlier tested positive for COVID-19 reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and were now reporting to the College of Dentistry for routine treatment after recovery. Objective evaluation of olfactory and gustatory disturbances was elicited using the Connecticut Chemosensory Clinical Research Center (CCCRC) test and gustatory function testing. Furthermore, OHRQoL was assessed using Oral Health Impact Profile (OHIP-14).

Results

More than half of the patients (62%) had some form of olfactory dysfunction/alteration, and 42% had poor CCCRC scores. About 14% reported ageusia, while 68% reported some form of taste alterations, and 55% reported poor OHRQoL. A statistically significant difference was reported between different ABO blood groups and subjective loss of smell (p < 0.05). The subjective loss of taste, CCCRC score, and dysgeusia were found to be independent of OHIP-14 (p > 0.05), but the taste intensity score was dependent on OHIP 14 (p < 0.05). Moreover, a majority (70.8% and 70.0%) with poor OHIP-14 scores had taste intensity scores of 3 and 4, respectively, while those with moderate (68.4% and 48.6%) OHIP-14 had scored 1 and 2, respectively.

Conclusion

Olfactory and gustatory disturbances were found to be a long-term feature in post-COVID-19 patients. The blood group is a predisposing factor for persistent smell alterations in post-COVID-19 patients.

Olfactory and gustatory disorders caused by COVID-19: How to regain the pleasure of eating?

Background

Recently, anosmia and ageusia (and their variations) have been reported as frequent symptoms of COVID-19. Olfactory and gustatory stimuli are essential in the perception and pleasure of eating. Disorders in sensory perception may influence appetite and the intake of necessary nutrients when recovering from COVID-19. In this short commentary, taste and smell disorders were reported and correlated for the first time with food science.

Scope and approach

The objective of this short commentary is to report that taste and smell disorders resulted from COVID-19 may impact eating pleasure and nutrition. It also points out important technologies and trends that can be considered and improved in future studies.

Key findings and conclusions

Firmer food textures can stimulate the trigeminal nerve, and more vibrant colors are able to increase the modulation of brain metabolism, stimulating pleasure. Allied to this, encapsulation technology enables the production of new food formulations, producing agonist and antagonist agents to trigger or block specific sensations. Therefore, opportunities and innovations in the food industry are wide and multidisciplinary discussions are needed.

A Cross-Sectional Study of Exposure Factors Associated with Seropositivity for SARS-CoV-2 Antibodies during the Second Epidemic Wave among a Sample of the University of Corsica (France)

This study aimed to estimate the seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection within the staff and student populations of the University of Corsica (France) during the second wave of the epidemic. Methods: A cross-sectional survey was conducted from 23 November 2020 to 31 January 2021. The participants underwent blood sampling using a fingerstick procedure and completed an anonymized questionnaire. Sera were tested for the presence of anti-SARS-CoV-2 IgG (ELISA-S) and, if positive, with an in-house virus neutralization test (VNT). Results: A total of 418 persons were included in the study. The overall seroprevalence was 12.8% (95% confidence interval (CI), 9.8–16.6%). A total of 15 (31%) of the 49 individuals who had a positive ELISA-S also had a positive VNT. Seropositivity was associated with living at the city campus during the week and on weekends (OR = 3.74 [1.40–12.00]), using public transportation/carpooling (OR = 2.00 [1.01–4.02]), and being in contact with a person who tested positive for SARS-CoV-2 (OR = 2.32 [1.20–4.40]). The main symptoms associated with seropositivity were “having had an acute respiratory infection” (OR = 3.05 [1.43–6.43]) and “experiencing loss of smell” (OR = 16.4 [5.87–50.7]). Conclusion: These results could be useful for SARS-CoV-2 prevention and control on university campuses.

Research Active Posterior Rhinomanometry Tomography Method for Nasal Breathing Determining Violations

This study analyzes the existing methods for studying nasal breathing. The aspects of verifying the results of rhinomanometric diagnostics according to the data of spiral computed tomography are considered, and the methodological features of dynamic posterior active rhinomanometry and the main indicators of respiration are also analyzed. The possibilities of testing respiratory olfactory disorders are considered, the analysis of errors in rhinomanometric measurements is carried out. In the conclusions, practical recommendations are given that have been developed for the design and operation of tools for functional diagnostics of nasal breathing disorders. It is advisable, according to the data of dynamic rhinomanometry, to assess the functioning of the nasal valve by the shape of the air flow rate signals during forced breathing and the structures of the soft palate by the residual nasopharyngeal pressure drop. It is imperative to take into account not only the maximum coefficient of aerodynamic nose drag, but also the values of the pressure drop and air flow rate in the area of transition to the turbulent quadratic flow regime. From the point of view of the physiology of the nasal response, it is necessary to look at the dynamic change to the current mode, given the hour of the forced response, so that it will ensure the maximum possible acidity in the legend. When planning functional rhinosurgical operations, it is necessary to apply the calculation method using computed tomography, which makes it possible to predict the functional result of surgery.

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.

The clinical course and diagnostic relevance of olfactory loss in a SARS-CoV-2 infection

Background: The acute onset of olfactory and/or gustatory dysfunction is a frequent complaint during the COVID-19 pandemic. It is predominantly reported by subjects with asymptomatic to mild disease severity during the early stage of the infection. The high prevalence of anosmia/dysosmia and/or ageusia/dysgeusia in this current era implements a strong correlation with a SARSCoV-2 infection and these symptoms could therefore be seen as important prodromes. The purpose of this study was to outline the occurrence, epidemiology and clinical course of olfactory and/or gustatory disorders in (suspected) COVID-19 cases and to analyse the diagnostic significance of these neurosensory dysfunctions. Methods: An online questionnaire was carried out which addressed 500 participants with new onset olfactory and/or gustatory impairment during the COVID-19 pandemic. Results: Acute olfactory and gustatory loss was reported by 487 (97.4%) and 464 (92.8%), respectively. A significant higher prevalence of neurosensory complaints was reported by women and people of younger age. The most prevalent concurrent symptoms were fatigue, headaches, nasal congestion, dry cough, rhinorrhoea and sneezing. The recovery rate after 8 weeks was 41.9% for olfactory impairment and 53.7% for gustatory impairment. Among the 93 subjects tested, 82 (88.2%) tested positive for SARSCoV-2. Conclusion: Olfactory and/or gustatory disorders are prevalent clinical findings during the COVID-19 pandemic. Neurosensory impairments, isolated or in association with other mild complaints, need to be addressed as potential symptoms of a SARS-CoV-2 infection and should be implemented as clinical markers.

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.

Wearable Sensors for Assessing the Role of Olfactory Training on the Autonomic Response to Olfactory Stimulation

Wearable sensors are nowadays largely employed to assess physiological signals derived from the human body without representing a burden in terms of obtrusiveness. One of the most intriguing fields of application for such systems include the assessment of physiological responses to sensory stimuli. In this specific regard, it is not yet known which are the main psychophysiological drivers of olfactory-related pleasantness, as the current literature has demonstrated the relationship between odor familiarity and odor valence, but has not clarified the consequentiality between the two domains. Here, we enrolled a group of university students to whom olfactory training lasting 3 months was administered. Thanks to the analysis of electrocardiogram (ECG) and galvanic skin response (GSR) signals at the beginning and at the end of the training period, we observed different autonomic responses, with higher parasympathetically-mediated response at the end of the period with respect to the first evaluation. This possibly suggests that an increased familiarity to the proposed stimuli would lead to a higher tendency towards relaxation. Such results could suggest potential applications to other domains, including personalized treatments based on odors and foods in neuropsychiatric and eating disorders.

Can symptoms of anosmia and dysgeusia be diagnostic for COVID-19?

OBJECTIVE

Olfactory and taste dysfunction (OTD) is a potential neurological manifestation of coronavirus-2019 (COVID-19). We aimed to investigate the diagnostic value of symptoms of anosmia and dysgeusia for COVID-19.

METHODS

A comprehensive electronic search was conducted using PubMed, MEDLINE, Scopus, Cochrane database, and Google Scholar from 1 June 2020 to 12 June 2020. All studies reporting symptoms of anosmia and dysgeusia in COVID-19-positive patients were included. A total of 23 studies were included in the systematic review.

RESULTS

Symptoms of anosmia and dysgeusia were frequently reported by COVID-19-positive patients. Symptoms were more common in females and in younger patients. There was no direct association between the severity of COVID-19 and the presence of symptoms. However, some evidence was found for a longer duration of these symptoms and increased severity of COVID-19 infection in young patients.

CONCLUSION

OTD is commonly reported by COVID-19 patients. Due to limited literature on the association between OTD and COVID-19, it is currently not possible to conclude that these symptoms alone can be used to diagnose COVID-19. However, the presence of OTD can potentially be used as a screening tool for COVID-19 especially in young and female patients. Further research is required to establish the true diagnostic value of these symptoms and efficacy as screening tools for COVID-19 patients.

Quantitative assessment of olfactory dysfunction accurately detects asymptomatic COVID-19 carriers

BACKGROUND

COVID-19 threatens the global community because a large fraction of infected people are asymptomatic, yet can effectively transmit SARS-CoV-2. Finding and isolating these silent carriers is a crucial step in confining the spread of the disease. A sudden loss of the sense of smell has been self-reported by COVID-19 patients across different countries, consistent with expression of the molecular factors mediating SARS-CoV-2 uptake into human olfactory epithelial supporting cells. However, precise quantification of olfactory loss in asymptomatic COVID-19 carriers is missing to date.

METHODS

To quantify olfactory functions in asymptomatic COVID-19 patients, we designed an olfactory-action meter that determines detectability indices at different odor concentrations and an olfactory matching accuracy score using monomolecular odors. The optimization of test parameters allowed us to reliably and accurately assess olfactory deficits in a patient within 20 minutes.

FINDINGS

Measurement of detection indices at low concentrations revealed a 50% reduction in asymptomatic COVID-19 carriers. Further, patients with better detection scores showed significantly reduced olfactory matching accuracies compared to normal healthy subjects. Our quantification of olfactory loss, considering all parameters, identified 82% of the asymptomatic SARS-CoV-2 carriers with olfactory deficits. However, on subjective evaluation, only 15% of the patients noticed a compromised ability to smell.

INTERPRETATION

Compromised olfactory fitness can serve as a strong basis for identifying asymptomatic COVID-19 patients. Detailed design specifications and protocols provided here should enable the development of a sensitive, fast, and economical screening strategy that can be administered to large populations to prevent the rapid spread of COVID-19.

FUNDING

This work was supported by the DBT - Wellcome Trust India Alliance intermediate grant (IA/I/14/1/501,306 to N.A.) and UGC NET Fellowship (A.B.). All the funding sources played no roles in the study.

[Sorting and detection of COVID-19 by low-dose thoracic CT scan in patients consulting the radiology department of Fann hospital (Dakar-Senegal)]

Introduction

COVID-19 has spread rapidly since its emergence in China and is currently a global health issue. Its definitive diagnosis is made by PCR on nasopharyngeal swabs. However, this diagnostic test has low sensitivity with delayed results. Hence, thoracic computed tomography represents an interesting alternative. The aims of this study were to assess the frequency of computed tomography (CT) lesions suggestive of COVID-19 and to compare the results of CT and PCR test.

Methods

a prospective study carried out over15 working days and involved 47 patients. These patients were recruited based on the presence of at least 2 clinical signs of COVID-19. Chest CT without contrast according to the "LOW-DOSE" protocol was performed. A PCR test on nasopharyngeal swabs was done in patients with signs suggestive of COVID on CT. A serological test was performed in case of a discrepancy between the CT and PCR results.

Results

thoracic CT was abnormal in 38 patients and normal in 9 patients. Lesions suggestive of COVID-19 have been identified in 32 patients. Two patients had lesions of non-specific pneumonia. Tuberculosis lesions were visualized in 3 patients. One patient had lesions of interstitial pneumonia. The mean DLP was 59 mGy.cm with extremes of 25 and 95 mGy.cm. Ground-glass opacity was present in 100% of COVID-19 suspects on CT. The results of the PCR test were the same than CT in 12 patients. The positive predictive value for CT was 37.5%. In 20 patients with COVID lesions on CT, the PCR test was negative with a false positive rate of 62.5%. In the patients with negative PCR test, 4 had a serological test for COVID-19 and this test was positive in 3.

Conclusion

low-dose chest CT can reduce radiation exposure in COVID-19 patients who are at risk of cumulative dose due to repetitive exam. CT can identify lesions suggestive of COVID-19. It also enables the triage of patients by identifying other diagnoses.