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Archives of Pharmacal Research Jul 2021Anecdotal evidence suggests that the severity of coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is...
Anecdotal evidence suggests that the severity of coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is likely to be distinguished by variations in loss of smell (LOS). Thus, we conducted a meta-analysis of 45 articles that include a total of 42,120 COVID-19 patients from 17 different countries to demonstrate that severely ill or hospitalized COVID-19 patients have a lesser chance of experiencing LOS than non-severely ill or non-hospitalized COVID-19 patients (odds ratio = 0.527 [95% CI 0.373-0.744; p < 0.001] and 0.283 [95% CI 0.173-0.462; p < 0.001], respectively). We also proposed a possible mechanism underlying the association of COVID-19 severity with anosmia, which may explain why patients without sense of smell develop severe COVID-19. Variations in LOS according to the severity of COVID-19 is a global phenomenon, with few exceptions. Since severely ill patients have a lower rate of anosmia, patients without anosmia should be monitored more closely in the early stages of COVID-19, for early diagnosis of severity of illness. An understanding of how the severity of COVID-19 infection and LOS are associated has profound implications for the clinical management and mitigation strategies for the disease.
Topics: Anosmia; COVID-19; Early Diagnosis; Female; Hospitalization; Humans; Male; Odorants; Olfactory Perception; Predictive Value of Tests; Prognosis; Risk Assessment; Risk Factors; Severity of Illness Index; Smell
PubMed: 34302637
DOI: 10.1007/s12272-021-01344-4 -
Acta Neuropathologica Communications May 2023COVID-19-infected patients harbour neurological symptoms such as stroke and anosmia, leading to the hypothesis that there is direct invasion of the central nervous...
INTRODUCTION
COVID-19-infected patients harbour neurological symptoms such as stroke and anosmia, leading to the hypothesis that there is direct invasion of the central nervous system (CNS) by SARS-CoV-2. Several studies have reported the neuropathological examination of brain samples from patients who died from COVID-19. However, there is still sparse evidence of virus replication in the human brain, suggesting that neurologic symptoms could be related to mechanisms other than CNS infection by the virus. Our objective was to provide an extensive review of the literature on the neuropathological findings of postmortem brain samples from patients who died from COVID-19 and to report our own experience with 18 postmortem brain samples.
MATERIAL AND METHODS
We used microscopic examination, immunohistochemistry (using two different antibodies) and PCR-based techniques to describe the neuropathological findings and the presence of SARS-CoV-2 virus in postmortem brain samples. For comparison, similar techniques (IHC and PCR) were applied to the lung tissue samples for each patient from our cohort. The systematic literature review was conducted from the beginning of the pandemic in 2019 until June 1st, 2022.
RESULTS
In our cohort, the most common neuropathological findings were perivascular haemosiderin-laden macrophages and hypoxic-ischaemic changes in neurons, which were found in all cases (n = 18). Only one brain tissue sample harboured SARS-CoV-2 viral spike and nucleocapsid protein expression, while all brain cases harboured SARS-CoV-2 RNA positivity by PCR. A colocalization immunohistochemistry study revealed that SARS-CoV-2 antigens could be located in brain perivascular macrophages. The literature review highlighted that the most frequent neuropathological findings were ischaemic and haemorrhagic lesions, including hypoxic/ischaemic alterations. However, few studies have confirmed the presence of SARS-CoV-2 antigens in brain tissue samples.
CONCLUSION
This study highlighted the lack of specific neuropathological alterations in COVID-19-infected patients. There is still no evidence of neurotropism for SARS-CoV-2 in our cohort or in the literature.
Topics: Humans; COVID-19; SARS-CoV-2; RNA, Viral; Lung; Central Nervous System; Nervous System Diseases
PubMed: 37165453
DOI: 10.1186/s40478-023-01566-1 -
The Cochrane Database of Systematic... Feb 2021The clinical implications of SARS-CoV-2 infection are highly variable. Some people with SARS-CoV-2 infection remain asymptomatic, whilst the infection can cause mild to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The clinical implications of SARS-CoV-2 infection are highly variable. Some people with SARS-CoV-2 infection remain asymptomatic, whilst the infection can cause mild to moderate COVID-19 and COVID-19 pneumonia in others. This can lead to some people requiring intensive care support and, in some cases, to death, especially in older adults. Symptoms such as fever, cough, or loss of smell or taste, and signs such as oxygen saturation are the first and most readily available diagnostic information. Such information could be used to either rule out COVID-19, or select patients for further testing. This is an update of this review, the first version of which published in July 2020.
OBJECTIVES
To assess the diagnostic accuracy of signs and symptoms to determine if a person presenting in primary care or to hospital outpatient settings, such as the emergency department or dedicated COVID-19 clinics, has COVID-19.
SEARCH METHODS
For this review iteration we undertook electronic searches up to 15 July 2020 in the Cochrane COVID-19 Study Register and the University of Bern living search database. In addition, we checked repositories of COVID-19 publications. We did not apply any language restrictions.
SELECTION CRITERIA
Studies were eligible if they included patients with clinically suspected COVID-19, or if they recruited known cases with COVID-19 and controls without COVID-19. Studies were eligible when they recruited patients presenting to primary care or hospital outpatient settings. Studies in hospitalised patients were only included if symptoms and signs were recorded on admission or at presentation. Studies including patients who contracted SARS-CoV-2 infection while admitted to hospital were not eligible. The minimum eligible sample size of studies was 10 participants. All signs and symptoms were eligible for this review, including individual signs and symptoms or combinations. We accepted a range of reference standards.
DATA COLLECTION AND ANALYSIS
Pairs of review authors independently selected all studies, at both title and abstract stage and full-text stage. They resolved any disagreements by discussion with a third review author. Two review authors independently extracted data and resolved disagreements by discussion with a third review author. Two review authors independently assessed risk of bias using the Quality Assessment tool for Diagnostic Accuracy Studies (QUADAS-2) checklist. We presented sensitivity and specificity in paired forest plots, in receiver operating characteristic space and in dumbbell plots. We estimated summary parameters using a bivariate random-effects meta-analysis whenever five or more primary studies were available, and whenever heterogeneity across studies was deemed acceptable.
MAIN RESULTS
We identified 44 studies including 26,884 participants in total. Prevalence of COVID-19 varied from 3% to 71% with a median of 21%. There were three studies from primary care settings (1824 participants), nine studies from outpatient testing centres (10,717 participants), 12 studies performed in hospital outpatient wards (5061 participants), seven studies in hospitalised patients (1048 participants), 10 studies in the emergency department (3173 participants), and three studies in which the setting was not specified (5061 participants). The studies did not clearly distinguish mild from severe COVID-19, so we present the results for all disease severities together. Fifteen studies had a high risk of bias for selection of participants because inclusion in the studies depended on the applicable testing and referral protocols, which included many of the signs and symptoms under study in this review. This may have especially influenced the sensitivity of those features used in referral protocols, such as fever and cough. Five studies only included participants with pneumonia on imaging, suggesting that this is a highly selected population. In an additional 12 studies, we were unable to assess the risk for selection bias. This makes it very difficult to judge the validity of the diagnostic accuracy of the signs and symptoms from these included studies. The applicability of the results of this review update improved in comparison with the original review. A greater proportion of studies included participants who presented to outpatient settings, which is where the majority of clinical assessments for COVID-19 take place. However, still none of the studies presented any data on children separately, and only one focused specifically on older adults. We found data on 84 signs and symptoms. Results were highly variable across studies. Most had very low sensitivity and high specificity. Only cough (25 studies) and fever (7 studies) had a pooled sensitivity of at least 50% but specificities were moderate to low. Cough had a sensitivity of 67.4% (95% confidence interval (CI) 59.8% to 74.1%) and specificity of 35.0% (95% CI 28.7% to 41.9%). Fever had a sensitivity of 53.8% (95% CI 35.0% to 71.7%) and a specificity of 67.4% (95% CI 53.3% to 78.9%). The pooled positive likelihood ratio of cough was only 1.04 (95% CI 0.97 to 1.11) and that of fever 1.65 (95% CI 1.41 to 1.93). Anosmia alone (11 studies), ageusia alone (6 studies), and anosmia or ageusia (6 studies) had sensitivities below 50% but specificities over 90%. Anosmia had a pooled sensitivity of 28.0% (95% CI 17.7% to 41.3%) and a specificity of 93.4% (95% CI 88.3% to 96.4%). Ageusia had a pooled sensitivity of 24.8% (95% CI 12.4% to 43.5%) and a specificity of 91.4% (95% CI 81.3% to 96.3%). Anosmia or ageusia had a pooled sensitivity of 41.0% (95% CI 27.0% to 56.6%) and a specificity of 90.5% (95% CI 81.2% to 95.4%). The pooled positive likelihood ratios of anosmia alone and anosmia or ageusia were 4.25 (95% CI 3.17 to 5.71) and 4.31 (95% CI 3.00 to 6.18) respectively, which is just below our arbitrary definition of a 'red flag', that is, a positive likelihood ratio of at least 5. The pooled positive likelihood ratio of ageusia alone was only 2.88 (95% CI 2.02 to 4.09). Only two studies assessed combinations of different signs and symptoms, mostly combining fever and cough with other symptoms. These combinations had a specificity above 80%, but at the cost of very low sensitivity (< 30%).
AUTHORS' CONCLUSIONS
The majority of individual signs and symptoms included in this review appear to have very poor diagnostic accuracy, although this should be interpreted in the context of selection bias and heterogeneity between studies. Based on currently available data, neither absence nor presence of signs or symptoms are accurate enough to rule in or rule out COVID-19. The presence of anosmia or ageusia may be useful as a red flag for COVID-19. The presence of fever or cough, given their high sensitivities, may also be useful to identify people for further testing. Prospective studies in an unselected population presenting to primary care or hospital outpatient settings, examining combinations of signs and symptoms to evaluate the syndromic presentation of COVID-19, are still urgently needed. Results from such studies could inform subsequent management decisions.
Topics: Ageusia; Ambulatory Care; Anosmia; Arthralgia; Bias; COVID-19; Cough; Diarrhea; Dyspnea; Fatigue; Fever; Headache; Humans; Myalgia; Outpatient Clinics, Hospital; Pandemics; Physical Examination; Primary Health Care; SARS-CoV-2; Selection Bias; Symptom Assessment
PubMed: 33620086
DOI: 10.1002/14651858.CD013665.pub2 -
MedRxiv : the Preprint Server For... Jun 2020A significant fraction of people who test positive for COVID-19 have chemosensory deficits. However, the reported prevalence of these deficits in smell and/or taste...
A significant fraction of people who test positive for COVID-19 have chemosensory deficits. However, the reported prevalence of these deficits in smell and/or taste varies widely, and the reason for the differences between studies is unclear. We determined the pooled prevalence of such chemosensory deficits in a systematic review. We searched the COVID-19 portfolio of the National Institutes of Health for all studies that reported the prevalence of smell and/or taste deficits in patients diagnosed with COVID-19. Forty-two studies reporting on 23,353 patients qualified and were subjected to a systematic review and meta-analysis. Estimated random prevalence of olfactory dysfunction was 38.5%, of taste dysfunction was 30.4% and of overall chemosensory dysfunction was 50.2%. We examined the effects of age, disease severity, and ethnicity on chemosensory dysfunction. The effect of age did not reach significance, but anosmia/hypogeusia decreased with disease severity, and ethnicity was highly significant: Caucasians had a 3-6 times higher prevalence of chemosensory deficits than East Asians. The finding of ethnic differences points to genetic, ethnicity-specific differences of the virus-binding entry proteins in the olfactory epithelium and taste buds as the most likely explanation, with major implications for infectivity, diagnosis and management of the COVID-19 pandemic.
PubMed: 32587993
DOI: 10.1101/2020.06.15.20132134 -
Journal of Neurology May 2021The novel severe acute respiratory syndrome (SARS)-CoV-2 outbreak has been declared a pandemic in March, 2020. An increasing body of evidence suggests that patients with...
OBJECT
The novel severe acute respiratory syndrome (SARS)-CoV-2 outbreak has been declared a pandemic in March, 2020. An increasing body of evidence suggests that patients with the coronavirus disease (COVID-19) might have a heterogeneous spectrum of neurological symptoms METHODS: A systematic search of two databases was performed for studies published up to May 29th, 2020. PRISMA guidelines were followed.
RESULTS
We included 19 studies evaluating 12,157 patients with laboratory-confirmed COVID-19 infections. The median age of patients was 50.3 (IQR 11.9), and the rate of male patients was 50.6% (95% CI 49.2-51.6%). The most common reported comorbidities were hypertension and diabetes (31.1%, 95% CI 30-32.3% and 13.5%, 95% CI 12.3-14.8%, respectively). Headache was reported in 7.5% of patients (95% CI 6.6-8.4%), and dizziness in 6.1% (95% CI 5.1-7.1%). Hypo/anosmia, and gustatory dysfunction were reported in 46.8 and 52.3%, of patients, respectively. Symptoms related to muscular injury ranged between 15 and 30%. Three studies reported radiological confirmed acute cerebrovascular disease in 2% of patients (95% CI 1.6-2.4%).
CONCLUSIONS
These data support accumulating evidence that a significant proportion of patients with COVID-19 infection develop neurological manifestations, especially olfactory, and gustatory dysfunction. The pathophysiology of this association is under investigation and warrants additional studies, Physicians should be aware of this possible association because during the epidemic period of COVID-19, early recognition of neurologic manifestations otherwise not explained would raise the suspect of acute respiratory syndrome coronavirus 2 infection.
Topics: COVID-19; Humans; Nervous System Diseases; Pandemics; SARS-CoV-2; United States
PubMed: 32740766
DOI: 10.1007/s00415-020-09978-y -
Clinical Otolaryngology : Official... Nov 2020To systematically review the currently available evidence investigating the association between olfactory dysfunction (OD) and the novel coronavirus (COVID-19). To... (Meta-Analysis)
Meta-Analysis
AIMS
To systematically review the currently available evidence investigating the association between olfactory dysfunction (OD) and the novel coronavirus (COVID-19). To analyse the prevalence of OD in patients who have tested positive on polymerase chain reaction (PCR) for COVID-19. To perform a meta-analysis of patients presenting with olfactory dysfunction, during the pandemic, and to investigate the positive predictive value for a COVID-19-positive result in this population. To assess whether olfactory dysfunction could be used as a diagnostic marker for COVID-19 positivity and aid public health approaches in tackling the current outbreak.
METHODS
We systematically searched MedLine (PubMed), Embase, Health Management Information Consortium (HMIC), Medrxiv, the Cochrane Library, the Cochrane COVID-19 Study Register, NIHR Dissemination centre, Clinical Evidence, National Health Service Evidence and the National Institute of Clinical Excellence to identify the current published evidence which associates coronaviridae or similar RNA viruses with anosmia. The initial search identified 157 articles. A total of 145 papers were excluded following application of our exclusion criteria. The 12 remaining articles that presented evidence on the association between COVID-19 and olfactory dysfunction were critically analysed.
RESULTS
Olfactory dysfunction has been shown to be the strongest predictor of COVID-19 positivity when compared to other symptoms in logistic regression analysis. In patients who had tested positive for COVID-19, there was a prevalence of 62% of OD. In populations of patients who are currently reporting OD, there is a positive predictive value of 61% for a positive COVID-19 result.
CONCLUSION
Our review has shown that there is already significant evidence which demonstrates an association between OD and the novel coronavirus-COVID-19. It is unclear if this finding is unique to this coronavirus as individual viral phenotypes rarely present in such concentrated large numbers. We have demonstrated that OD is comparatively more predictive for COVID-19 positivity compared to other associated symptoms. We recommend that people who develop OD during the pandemic should be self-isolate and this guidance should be adopted internationally to prevent transmission.
Topics: COVID-19; COVID-19 Nucleic Acid Testing; Humans; Olfaction Disorders; Predictive Value of Tests; Prevalence; Reverse Transcriptase Polymerase Chain Reaction
PubMed: 32741085
DOI: 10.1111/coa.13620 -
American Journal of Rhinology & Allergy May 2021Post-viral olfactory dysfunction is a common cause of both short- and long-term smell alteration. The coronavirus pandemic further highlights the importance of...
BACKGROUND
Post-viral olfactory dysfunction is a common cause of both short- and long-term smell alteration. The coronavirus pandemic further highlights the importance of post-viral olfactory dysfunction. Currently, a comprehensive review of the neural mechanism underpinning post-viral olfactory dysfunction is lacking.
OBJECTIVES
To synthesize the existing primary literature related to olfactory dysfunction secondary to viral infection, detail the underlying pathophysiological mechanisms, highlight relevance for the current COVID-19 pandemic, and identify high impact areas of future research.
METHODS
PubMed and Embase were searched to identify studies reporting primary scientific data on post-viral olfactory dysfunction. Results were supplemented by manual searches. Studies were categorized into animal and human studies for final analysis and summary.
RESULTS
A total of 38 animal studies and 7 human studies met inclusion criteria and were analyzed. There was significant variability in study design, experimental model, and outcome measured. Viral effects on the olfactory system varies significantly based on viral substrain but generally include damage or alteration in components of the olfactory epithelium and/or the olfactory bulb.
CONCLUSIONS
The mechanism of post-viral olfactory dysfunction is highly complex, virus-dependent, and involves a combination of insults at multiple levels of the olfactory pathway. This will have important implications for future diagnostic and therapeutic developments for patients infected with COVID-19.
Topics: Animals; COVID-19; Humans; Olfaction Disorders; Olfactory Bulb; Olfactory Mucosa; Olfactory Pathways; SARS-CoV-2; Species Specificity; Post-Acute COVID-19 Syndrome
PubMed: 32915650
DOI: 10.1177/1945892420957853 -
The Cochrane Database of Systematic... Sep 2020COVID-19 infection poses a serious risk to patients and - due to its contagious nature - to those healthcare workers (HCWs) treating them. If the mouth and nose of...
BACKGROUND
COVID-19 infection poses a serious risk to patients and - due to its contagious nature - to those healthcare workers (HCWs) treating them. If the mouth and nose of HCWs are irrigated with antimicrobial solutions, this may help reduce the risk of active infection being passed from infected patients to HCWs through droplet transmission or direct contact. However, the use of such antimicrobial solutions may be associated with harms related to the toxicity of the solutions themselves, or alterations in the natural microbial flora of the mouth or nose. Understanding these possible side effects is particularly important when the HCWs are otherwise fit and well.
OBJECTIVES
To assess the benefits and harms of antimicrobial mouthwashes and nasal sprays used by healthcare workers (HCWs) to protect themselves when treating patients with suspected or confirmed COVID-19 infection.
SEARCH METHODS
Information Specialists from Cochrane ENT and Cochrane Oral Health searched the Central Register of Controlled Trials (CENTRAL 2020, Issue 6); Ovid MEDLINE; Ovid Embase and additional sources for published and unpublished trials. The date of the search was 1 June 2020. SELECTION CRITERIA: This is a question that urgently requires evidence, however at the present time we did not anticipate finding many completed randomised controlled trials (RCTs). We therefore planned to include the following types of studies: RCTs; quasi-RCTs; non-randomised controlled trials; prospective cohort studies; retrospective cohort studies; cross-sectional studies; controlled before-and-after studies. We set no minimum duration for the studies. We sought studies comparing any antimicrobial mouthwash and/or nasal spray (alone or in combination) at any concentration, delivered to HCWs, with or without the same intervention being given to the patients with COVID-19.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methodological procedures. Our primary outcomes were: 1) incidence of symptomatic or test-positive COVID-19 infection in HCWs; 2) significant adverse event: anosmia (or disturbance in sense of smell). Our secondary outcomes were: 3) viral content of aerosol, when present (if intervention administered to patients); 4) other adverse events: changes in microbiome in oral cavity, nasal cavity, oro- or nasopharynx; 5) other adverse events: allergy, irritation/burning of nasal, oral or oropharyngeal mucosa (e.g. erosions, ulcers, bleeding), long-term staining of mucous membranes or teeth, accidental ingestion. We planned to use GRADE to assess the certainty of the evidence for each outcome.
MAIN RESULTS
We found no completed studies to include in this review. We identified three ongoing studies (including two RCTs), which aim to enrol nearly 700 participants. The interventions included in these trials are povidone iodine, nitric oxide and GLS-1200 oral spray (the constituent of this spray is unclear and may not be antimicrobial in nature). AUTHORS' CONCLUSIONS: We identified no studies for inclusion in this review. This is not surprising given the relatively recent emergence of COVID-19 infection. It is promising that the question posed in this review is being addressed by two RCTs and a non-randomised study. We are concerned that only one of the ongoing studies specifically states that it will evaluate adverse events and it is not clear if this will include changes in the sense of smell or to the oral and nasal microbiota, and any consequences thereof. Very few interventions have large and dramatic effect sizes. If a positive treatment effect is demonstrated when studies are available for inclusion in this review, it may not be large. In these circumstances in particular, where those receiving the intervention are otherwise fit and well, it may be a challenge to weigh up the benefits against the harms if the latter are of uncertain frequency and severity.
Topics: Anti-Infective Agents; Betacoronavirus; COVID-19; Coronavirus Infections; Health Personnel; Humans; Infectious Disease Transmission, Patient-to-Professional; Mouth; Mouthwashes; Nasal Sprays; Nose; Occupational Diseases; Pandemics; Pneumonia, Viral; SARS-CoV-2; Therapeutic Irrigation
PubMed: 32936949
DOI: 10.1002/14651858.CD013626.pub2 -
Acta Otorrinolaringologica Espanola 2020There is debate as to whether olfactory dysfunction should be considered a symptom of COVID-19 infection, given the implications for managing the symptom itself, for...
There is debate as to whether olfactory dysfunction should be considered a symptom of COVID-19 infection, given the implications for managing the symptom itself, for diagnostic testing, and for implementing isolation measures. We undertook a systematic literature review of the articles indexed in PubMed on olfactory disorders in viral respiratory tract conditions, with special emphasis on COVID-19. The main objective was to find evidence of clinical interest to support the relationship between anosmia and COVID-19. Olfactory disorders in upper respiratory tract infections are frequent, most caused by obstruction due to oedema of the nasal mucosa. Occasionally, post-viral sensorineural olfactory dysfunction occurs, with a variable prognosis. The evidence on anosmia in COVID-19 patients is extremely limited, corresponding to a level 5 or D of the Centre for Evidence-Based Medicine. According to the various medical societies that have issued reports on the subject, it seems reasonable to apply isolation, hygiene and social distancing measures in patients with recent olfactory disorders as the only symptom, although the usefulness of diagnostic tests for this type of patient should be studied.
Topics: Betacoronavirus; COVID-19; COVID-19 Testing; Clinical Laboratory Techniques; Coronavirus Infections; Humans; Hygiene; Olfaction Disorders; Olfactory Mucosa; Pandemics; Patient Isolation; Pneumonia, Viral; Practice Guidelines as Topic; Prognosis; Quarantine; Respiratory Tract Infections; SARS-CoV-2; Virus Diseases
PubMed: 32466862
DOI: 10.1016/j.otorri.2020.04.003 -
MedRxiv : the Preprint Server For... Jul 2020Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has currently infected over 6.5 million people worldwide....
Objective sensory testing methods reveal a higher prevalence of olfactory loss in COVID-19-positive patients compared to subjective methods: A systematic review and meta-analysis.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has currently infected over 6.5 million people worldwide. In response to the pandemic, numerous studies have tried to identify causes and symptoms of the disease. Emerging evidence supports recently acquired anosmia (complete loss of smell) and hyposmia (partial loss of smell) as symptoms of COVID-19, but studies of olfactory dysfunction show a wide range of prevalence, from 5% to 98%. We undertook a search of Pubmed/Medline and Google Scholar with the keywords "COVID-19," "smell," and/or "olfaction." We included any study that quantified olfactory loss as a symptom of COVID-19. Studies were grouped and compared based on the type of method used to measure smell loss-subjective measures such as self-reported smell loss versus objective measures using rated stimuli-to determine if prevalence rate differed by method type. For each study, 95% confidence intervals (CIs) were calculated from point estimates of olfactory disturbance rates. We identified 34 articles quantifying anosmia as a symptom of COVID-19, collected from cases identified from January 16 to April 30, 2020. The pooled prevalence estimate of smell loss was 77% when assessed through objective measurements (95% CI of 61.4-89.2%) and 45% with subjective measurements (95% CI of 31.1-58.5%). Objective measures are a more sensitive method to identify smell loss as a result of infection with SARS-CoV-2; the use of subjective measures, while expedient during the early stages of the pandemic, underestimates the true prevalence of smell loss.
PubMed: 32676608
DOI: 10.1101/2020.07.04.20145870