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

Prevalence and Prognostic Factors Associated with Early Recovery of Olfactory Dysfunction in COVID-19 Patients

BACKGROUND

The prevalence of smell dysfunction, along with its risk factors, has been evaluated in previous literature; however, little has been established regarding its relation to other factors such as disease severity, history of coronavirus disease-2019 (COVID-19) vaccinations, and medical treatment for COVID-19 infection. These factors may impact the overall recovery of olfaction in COVID-19 patients.

OBJECTIVE

This study investigated the prevalence of early olfactory recovery from COVID-19 infection and its associated factors.

METHODS

This study was a prospective cohort study on 348 COVID-19 patients with a new onset of anosmia or hyposmia. Smell sensation scores on the olfactory self-assessment test were collected at baseline and every week until 6 weeks of follow-up. The primary outcome was the prevalence of early olfactory recovery. The secondary outcomes were analyzing factors associated with early olfactory recovery and the median time to complete recovery of smell loss.

RESULTS

The prevalence of early olfactory recovery was 63.1% (95% CI: 0.58-0.68), and significant associated factors in multivariate analysis included patients without allergic rhinitis (OR 2.22, 95% CI: 1.12-4.40, P = 0.023) and no alteration of taste perception (OR 1.62, 95% CI: 1.02-2.57, P = 0.042). The median time to complete recovery from smell loss was 2 weeks.

CONCLUSION

The present study found that the prevalence of early olfactory recovery within 2 weeks was 63.1%. The median time to olfactory recovery was also 2 weeks. Patients without allergic rhinitis and taste alteration had a significantly better chance of early recovery of olfactory function.

Understanding the olfactory role in post-COVID cognitive and neuropsychiatric manifestations

Introduction

Olfactory dysfunction (OD) is frequent after SARS-CoV-2 infection. The aim of this study was to examine if long-term OD is common in post-COVID condition, and the relationship between olfaction, cognition, neuropsychiatric symptoms, and disease duration in these patients.

Methods

This study included 121 participants with post-COVID condition and 51 healthy controls (HC). A comprehensive neuropsychological and neuropsychiatric assessment was conducted, encompassing various domains, including general cognition, processing speed, verbal fluency, attention, verbal memory, visual memory, visuoconstructive ability, visuospatial ability, abstraction, executive functions, anxious-depressive symptoms, general health perception, fatigue level, sleep quality, and olfaction. Statistical analyses were carried out to understand the relationship of OD with cognition, and its role as moderator variable.

Results

In total, 25% of the post-covid patients had a reduced smell capacity, while only 9.3% of HC presented OD. Post-COVID patients had statistically significantly worse cognitive performance and clinical status than HC. Verbal fluency (AUC = 0.85, p < 0.001), and attention (AUC = 0.82, p < 0.001) were the variables that best discriminate between groups. OD seemed to be a moderator between fatigue and cognition, and between disease duration and attention (β = -0.04; p = 0.014).

Discussion

The study highlights marked cognitive and neuropsychiatric sequelae in individuals post-COVID relative to HC. Olfactory impairment exhibits correlations with both cognitive performance and general health. Olfaction emerges as a potential prognostic marker owing to its moderating influence on disease severity indicators.

Post-COVID-19: Time to Change Our Way of Life for a Better Future

Background and Objectives: From the year 1 anno Domini until 1855, with the third plague, major pandemics occurred on average every 348 years. Since then, they have occurred on average every 33 years, with coronavirus disease 2019 (COVID-19) now underway. Even though current technologies have greatly improved the way of life of human beings, COVID-19, with more than 700,000,000 cases and 6,950,000 deaths worldwide by the end of 2023, reminds us that much remains to be done. This report looks back at 18 months of COVID-19, from March 2020 to August 2021, with the aim of highlighting potential solutions that could help mitigate the impact of future pandemics. Materials and Methods: COVID-19 data, including case and death reports, were extracted daily from the Worldometer platform to build a database for the macroscopic analysis of the spread of the virus around the world. Demographic data were integrated into the COVID-19 database for a better understanding of the spatial spread of the SARS-CoV-2 virus in cities/municipalities. Without loss of generality, only data from the top 30 (out of 200 and above) countries ranked by total number of COVID-19 cases were analyzed. Statistics (regression, t-test (p < 0.05), correlation, mean ± std, etc.) were carried out with Excel software (Microsoft® Excel® 2013 (15.0.5579.1001)). Spectral analysis, using Matlab software (license number: 227725), was also used to try to better understand the temporal spread of COVID-19. Results: This study showed that COVID-19 mainly affects G20 countries and that cities/municipalities with high population density are a powerful activator of the spread of the virus. In addition, spectral analysis highlighted that the very first months of the spread of COVID-19 were the most notable, with a strong expansion of the SARS-CoV-2 virus. On the other hand, the following six months showed a certain level of stability, mainly due to multiple preventive measures such as confinement, the closure of non-essential services, the wearing of masks, distancing of 2 m, etc. Conclusion: Given that densely populated cities and municipal areas have largely favored the spread of the SARS-CoV-2 virus, it is believed that such a demographic context is becoming a societal problem that developed countries must address in a manner that is adequate and urgent. COVID-19 has made us understand that it is time to act both preventatively and curatively. With phenomenological evidence suggesting that the next pandemic could occur in less than 50 years, it may be time to launch new societal projects aimed at relieving congestion in densely populated regions.

Headache Associated with Coronavirus Disease 2019

Headache affects around half of patients in the acute phase of COVID-19 and generally occurs at the beginning of the symptomatic phase, has an insidious onset, and is bilateral, and of moderate to severe intensity. COVID-19 may also present complications that cause acute and persistent headaches, such as cerebrovascular diseases, rhinosinusitis, meningitis, and intracranial hypertension. In 10% to 20% of patients with COVID-19, headache may persist beyond the acute phase. In general, the headache improves over time. To date, there are no clinical trials that have assessed the treatment of persistent post-COVID-19 headache.

Remote olfactory assessment using the NIH Toolbox Odor Identification test and the brain health registry

BACKGROUND

Early identification of deficits in our ability to perceive odors is important as many normal (i.e., aging) and pathological (i.e., sinusitis, viral, neurodegeneration) processes can result in diminished olfactory function. To realistically enable population-level measurements of olfaction, validated olfaction tests must be capable of being administered outside the research laboratory and clinical setting.

AIM

The purpose of this study was to determine the feasibility of remotely testing olfactory performance using a test that was developed with funding from the National Institutes of Health as part of a ready-to-use, non-proprietary set of measurements useful for epidemiologic studies (NIH Toolbox Odor ID Test).

MATERIALS AND METHODS

Eligible participants older than 39 years and active (within 6 months) in the Brain Health Registry (BHR), an online cognitive assessment platform which connects participants with researchers, were recruited for this study. Interested participants were mailed the NIH Toolbox Odor ID Test along with instructions on accessing a website to record their responses. Data obtained from subjects who performed the test at home was compared to the normative data collected when the NIH Toolbox Odor ID Test was administered by a tester in a research setting and validated against the Smell Identification Test. The age-range and composition of the population ensured we had the ability to observe both age-related decline and gender-related deficits in olfactory ability, as shown in the experimental setting.

RESULTS

We observed that age-associated olfactory decline and gender-associated performance was comparable to performance on the administered test. Self-administration of this test showed the age-related loss in olfactory acuity, F(4, 1156)=14.564, p<.0001 as well as higher accuracy for women compared to men after controlling for participants' age, F(1, 1160) = 22.953, p <.0001. The effect size calculated as Hedge's g, was 0.41.

CONCLUSION

These results indicate that the NIH Toolbox Odor ID Test is an appropriate instrument for self-administered assessment of olfactory performance. The ability to self-administer an inexpensive olfactory test increases its utility for inclusion in longitudinal epidemiological studies and when in-person testing is not feasible.

A liquid chromatography-tandem mass spectrometry method development for the quantification of favipiravir drug and its related impurities in rat plasma and its application to pharmacokinetic studies

Favipiravir is an antiviral drug used for the treatment of virus-based diseases such as influenza. In this context, the development of a reliable liquid chromatography-tandem mass spectrometry method for the quantification of the drug and its impurities is necessary, particularly following the COVID-19 pandemic. Chromatographic separation was achieved on an inertial ODS column using gradient elution with a buffer containing triethylamine in high-performance liquid chromatography water and adjusting its pH with formic acid. The mixture of buffer and acetonitrile was used as a mobile phase with a flow rate of 1 ml/min at ambient temperature. The separation of favipiravir and its related impurities from remdesivir as an internal standard was achieved. The results indicated that all the variables, like precision, accuracy, linearity, matrix effect and stability, were successfully achieved within the limits of US Food and Drug Administration guidelines. This study could provide a new protocol for the development of new analytical methods for the detection of favipiravir and its impurities.

Type 2 and Non-type 2 Inflammation in the Upper Airways: Cellular and Molecular Alterations in Olfactory Neuroepithelium Cell Populations

PURPOSE OF REVIEW

Neurogenesis occurring in the olfactory epithelium is critical to continuously replace olfactory neurons to maintain olfactory function, but is impaired during chronic type 2 and non-type 2 inflammation of the upper airways. In this review, we describe the neurobiology of olfaction and the olfactory alterations in chronic rhinosinusitis with nasal polyps (type 2 inflammation) and post-viral acute rhinosinusitis (non-type 2 inflammation), highlighting the role of immune response attenuating olfactory neurogenesis as a possibly mechanism for the loss of smell in these diseases.

RECENT FINDINGS

Several studies have provided relevant insights into the role of basal stem cells as direct participants in the progression of chronic inflammation identifying a functional switch away from a neuro-regenerative phenotype to one contributing to immune defense, a process that induces a deficient replacement of olfactory neurons. The interaction between olfactory stem cells and immune system might critically underlie ongoing loss of smell in type 2 and non-type 2 inflammatory upper airway diseases. In this review, we describe the neurobiology of olfaction and the olfactory alterations in type 2 and non-type 2 inflammatory upper airway diseases, highlighting the role of immune response attenuating olfactory neurogenesis, as a possibly mechanism for the lack of loss of smell recovery.

The molecular fingerprint of neuroinflammation in COVID-19: A comprehensive discussion on molecular mechanisms of neuroinflammation due to SARS-COV2 antigens

BACKGROUND AND OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 attacks the neural system directly and indirectly via various systems, such as the nasal cavity, olfactory system, and facial nerves. Considering the high energy requirement, lack of antioxidant defenses, and high amounts of metal ions in the brain, oxidative damage is very harmful to the brain. Various neuropathic pain conditions, neurological disorders, and neuropsychiatric complications were reported in Coronavirus disease 2019, prolonged Coronavirus disease 2019, and after Coronavirus disease 2019 immunization. This manuscript offers a distinctive outlook on the interconnectedness between neurology and neuropsychiatry through its meticulous analysis of complications.

DISCUSSION

After recovering from Coronavirus disease 2019, approximately half of the patients reported developing Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. Long Coronavirus disease 2019 imaging reports illustrated the hypometabolism in various parts of the brain, such as olfactory bulbs, limbic/paralimbic domains, the brainstem, and the cerebellum. Ninety imaging and neuropathological studies of Coronavirus disease 2019 have shown evidence of white matter, brainstem, frontotemporal, and oculofrontal lesions. Emotional functions, such as pleasant, long/short-term memory, movement, cognition and cognition in decision-making are controlled by these regions. The neuroinflammation and the mechanisms of defense are well presented in the discussion. The role of microglia activation, Inducible NO synthase, Cyclooxygenases ½, Reactive oxygen species, neurotoxic toxins and pro-inflammatory cytokines, such as Interleukin-1 beta, Interleukin-6 and Tumor Necrosis Factor-alpha are highlighted in neuronal dysfunction and death. Nuclear factor kappa-light-chain-enhancer of activated B cells, Mitogen-activated protein kinase, Activator Protein 1, and Interferon regulatory factors are the main pathways involved in microglia activation in Coronavirus disease 2019 neuroinflammation.

CONCLUSION

The neurological aspect of Coronavirus disease 2019 should be highlighted. Neurological, psychological, and behavioral aspects of Coronavirus disease 2019, prolonged Coronavirus disease 2019, and Coronavirus disease 2019 vaccines can be the upcoming issues. We need a global awareness where this aspect of the disease should be more considered in health research.

Alcohol Sniff Test (AST): An Important Tool for Screening Post-Viral Olfactory Loss in Acute Flu-Like Dysfunction

Olfactory disorders have a significant impact on patients' quality of life but are often underestimated in clinical practice. Upper respiratory tract infections (URTIs) are a common cause of olfactory loss. While most cases of olfactory loss due to URTIs are conductive and reversible, post-viral olfactory dysfunction (PVOD) persists despite symptom improvement. PVOD is attributed to damage to the olfactory epithelium and nerves or central olfactory pathway lesions. The Alcohol Sniff Test (AST) has been proposed as a tool to assess olfactory function in the acute phase and aid in differentiating PVOD from conductive disorders. This study aims to evaluate the effectiveness of the AST as a predictor of post-viral olfactory loss in patients with flu-like syndrome. An observational cross-sectional study was conducted among employees with flu-like syndrome at a tertiary hospital. Three groups were formed: flu-like syndrome with conductive disorder without COVID-19 (PVOD-), flu-like syndrome with neurosensory and/or central disorder due to COVID-19 (PVOD +), and an asymptomatic control group. The Alcohol Sniff Test was performed to assess olfactory function. Statistical analysis was conducted to evaluate the AST's performance. For a cut off of 10 cm, 88.57% of PVOD + patients and 60.53% of PVOD - patients showed AST alteration, respectively (p = 0.013, OR = 5.05, 95% CI [1.48-17.25]). There was a statistically significant difference in the mean distance between the PVOD + group (4.35 ± 4.1 cm) and the control group (20 ± 4.33 cm) (p < 0.05). This relationship was also observed between the PVOD + and PVOD- groups (9 cm ± 7.5) (p < 0.05) and between the PVOD- and control groups (p < 0.05). For a cut off of 10 cm, the AST showed a sensitivity of 88% and specificity of 41%, resulting in an Odds Ratio of 9.7 (95% CI 3.3-28.1) (p < 0.001) and a Positive Predictive Value of 69.4% for PVOD. PVOD, including cases associated with COVID-19, is a prevalent cause of olfactory loss. The Alcohol Sniff Test demonstrated promising results in identifying PVOD in patients with flu-like syndrome. The test's simplicity and accessibility make it a valuable tool for early screening and identifying individuals who may benefit from prompt treatment. The Alcohol Sniff Test (AST) shows potential as an effective tool for screening post-viral olfactory loss in patients with flu-like syndrome. It can aid in early identification of PVOD cases and facilitate timely interventions to reduce the likelihood of persistent hyposmia.

Subjective Smell Disturbances in Children with Sars-Cov-2 or Other Viral Infections do not Correspond with Olfactory Test Results

BACKGROUND

Olfactory dysfunction associated with SARS-CoV-2 infection in children has not been verified by a validated olfactory test. We aimed to determine whether these complaints are objectifiable (test-based hyposmia), how often they occur during acute SARS-CoV-2 infection compared to other upper respiratory tract infections (URTI), as well as in children recovered from COVID-19 compared to children with long COVID.

METHODS

Olfactory testing (U-sniff test; hyposmia<8 points) and survey-based symptom assessments were performed in 434 children (5-17 years; 04/2021-06/2022). 186 symptom-free children served as controls. Of the children with symptoms of acute respiratory tract infection, SARS-CoV-2 PCR test results were positive in 45 and negative in 107 children (URTI group). Additionally, 96 children were recruited at least 4 weeks (17.6±15.2 weeks) after COVID-19, of whom 66 had recovered and 30 had developed long COVID.

RESULTS

Compared to controls (2.7%), hyposmia frequency was increased in all other groups (11-17%, p<0.05), but no between-group differences were observed. Only 3/41 children with hyposmia reported complaints, whereas 13/16 children with complaints were normosmic, with the largest proportion being in the long-COVID group (23%, p<0.05).

CONCLUSION

Questionnaires are unsuitable for assessing hyposmia frequency in children. Olfactory complaints and hyposmia are not specific for SARS-CoV-2 infection. The number of complaints in the long-COVID group could result from aversive olfactory perception, which is undetectable with the U-sniff test.

Virus-induced brain pathology and the neuroinflammation-inflammation continuum: the neurochemists view

Fascinatingly, an abundance of recent studies has subscribed to the importance of cytotoxic immune mechanisms that appear to increase the risk/trigger for many progressive neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), amyotrophic lateral sclerosis, and multiple sclerosis. Events associated with the neuroinflammatory cascades, such as ageing, immunologic dysfunction, and eventually disruption of the blood-brain barrier and the "cytokine storm", appear to be orchestrated mainly through the activation of microglial cells and communication with the neurons. The inflammatory processes prompt cellular protein dyshomeostasis. Parkinson's and Alzheimer's disease share a common feature marked by characteristic pathological hallmarks of abnormal neuronal protein accumulation. These Lewy bodies contain misfolded α-synuclein aggregates in PD or in the case of AD, they are Aβ deposits and tau-containing neurofibrillary tangles. Subsequently, these abnormal protein aggregates further elicit neurotoxic processes and events which contribute to the onset of neurodegeneration and to its progression including aggravation of neuroinflammation. However, there is a caveat for exclusively linking neuroinflammation with neurodegeneration, since it's highly unlikely that immune dysregulation is the only factor that contributes to the manifestation of many of these neurodegenerative disorders. It is unquestionably a complex interaction with other factors such as genetics, age, and environment. This endorses the "multiple hit hypothesis". Consequently, if the host has a genetic susceptibility coupled to an age-related weakened immune system, this makes them more susceptible to the virus/bacteria-related infection. This may trigger the onset of chronic cytotoxic neuroinflammatory processes leading to protein dyshomeostasis and accumulation, and finally, these events lead to neuronal destruction. Here, we differentiate "neuroinflammation" and "inflammation" with regard to the involvement of the blood-brain barrier, which seems to be intact in the case of neuroinflammation but defect in the case of inflammation. There is a neuroinflammation-inflammation continuum with regard to virus-induced brain affection. Therefore, we propose a staging of this process, which might be further developed by adding blood- and CSF parameters, their stage-dependent composition and stage-dependent severeness grade. If so, this might be suitable to optimise therapeutic strategies to fight brain neuroinflammation in its beginning and avoid inflammation at all.

Publication bias in otorhinolaryngology meta-analyses in 2021

INTRODUCTION

One concern in meta-analyses is the presence of publication bias (PB) which leads to the dissemination of inflated results. In this study, we assessed how much the meta-analyses in the field of otorhinolaryngology in 2021 evaluated the presence of PB.

METHODS

Six of the most influential journals in the field were selected. A search was conducted, and data were extracted from the included studies. In cases where PB was not assessed by the authors, we evaluated the risk of its presence by designing funnel plots and performing statistical tests.

RESULTS

Seventy-five systematic reviews were included. Fifty-one percent of them used at least one method for assessing the risk of PB, with the visual inspection of a funnel plot being the most frequent method used. Twenty-nine percent of the studies reported a high risk of PB presence. We replicated the results of 11 meta-analyses that did not assess the risk of PB and found that 63.6% were at high risk. We also found that a considerable proportion of the systematic reviews that found a high risk of PB did not take it into consideration when making conclusions and discussing their results.

DISCUSSION

Our results indicate that systematic reviews published in some of the most influential journals in the field do not implement enough measures in their search strategies to reduce the risk of PB, nor do they assess the risk of its presence or take the risk of its presence into consideration when inferring their results.

N. A Comparative Study on the General and Otolaryngological Manifestations of COVID-19 in the Hospitalized Population of the Telangana Region During the First and Second Waves

Introduction  Some common symptoms of coronavirus disease 2019 (COVID-19) are fever, cough, and shortness of breath. But ear, nose, and throat (ENT) manifestations such as loss of smell and taste are also very common. Objectives  To compare the general and otorhinolaryngological manifestations of COVID-19 and to compare the treatments given and mortality rate during its two waves. Methods  This retrospective study was conducted on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases in a tertiary care teaching hospital. Six hundred patients were included in the 1st wave sample and 516 were in the 2nd wave sample. The data collected included demographics, comorbidities, general, and ENT symptoms, need for ventilatory support, oxygen therapy, and mortality for both the waves. Results  Fever, malaise, and myalgia were more frequently presented in the first wave than in the second, whereas shortness of breath was more common in the second wave. In the second wave, a significant increase in anosmia cases was reported, whereas sore throat, nasal obstruction, dysphagia, nasal discharge, and sneezing were significantly reduced compared with the first wave ( p  < 0.001). The case fatality rate increased from 11.33 to 21.55% ( p  < 0.001) from the 1 st to the 2 nd wave. The patients who died in the second wave were younger than those in the first wave. Two doses of vaccination showed protection from the death over those not vaccinated and those who only received one dose ( p  < 0.05). Conclusion  Ear, nose, and throat (ENT) manifestations are very common along with the general symptoms. As anosmia and dysgeusia are early presenting symptoms in COVID-19 patients, all physicians should screen patients for ENT symptoms.

[Features of olfactory impairment connected with trigeminal nerve system]

Data on the state of sense of smell in patients who had a new coronavirus infection caused by the SARS-CoV-2 virus are currently reduced because of the impairment of the olfactory nerve system. There are practically no results in studies of disorders in the trigeminal nerve system.

OBJECTIVE

Qualitative assessment of olfactory disorders after COVID-19 according to the system of olfactory and trigeminal nerves with a targeted assessment of the functional component of olfactory disorders.

MATERIAL AND METHODS

We examined 40 patients aged 19 to 66 who had a coronavirus infection. All patients underwent neurological, otorhinolaryngological examinations, olfactometry, filled out the hospital anxiety and depression scale.

RESULTS

Anosmia was diagnosed in 5 (12.5%) patients, hyposmia in 21 (52.5%) patients, and normosmia in 14 (35%) patients. Formed: the 1st group - 14 patients (35%) with normogram according to olfactometry; the 2nd group - 26 patients (65%) with anosmia/hyposmia. In the 1st group, disorders of the anxiety-depressive spectrum were significantly more common. In the 2nd group, a low identification of odors was found, lying in the spectrum of fresh, sharp, unpleasant, irritating, compared with sweet and pleasant or neutral, which indicates a predominant lesion of the trigeminal system.

CONCLUSION

In patients with complaints of impaired sense of smell after undergoing COVID-19, the possible functional nature of anosmia/hyposmia should be taken into account, which requires the referral of such patients to psychotherapeutic specialists, and the possible entry of olfactory disorders into the 'trigeminal' spectrum.

Coronavirus infection and systemic inflammatory reaction syndrome

OBJECTIVE

Aim: The purpose of this study was a clinical approbation of the Kometad drug (international non-proprietary name sodium colistimethate), an antibiotic from the polymyxin group in patients with severe course of confirmed сoronavirus infection in the intensive care unit of the Branch of the I. Zhekenova Municipal Clinical Infectious Diseases Hospital..

PATIENTS AND METHODS

Materials and Methods: The methodology is based on both theoretical and empirical methods of scientific cognition. During the study, the features of the Coronavirus infection and the inflammatory reaction syndrome were considered, which became quite a big problem during the pandemic.

RESULTS

Results: The main indications for the tested drug and the consequences of its use for one age group were also determined.

CONCLUSION

Conclusions: The conclusion was made about the positive dynamics of the patients' health status, and recommendations were given for further research in this area. The practical significance of this study lies in the first clinical approbation of the Kometad drug, which can be used in medicine to reduce the severity of the systemic inflammatory reaction syndrome and improve the patient's health as a result of the disease of Coronavirus infection, after further clinical trials of the drug with different age groups of patients.

Corticosteroids for COVID-19-induced olfactory dysfunction: A comprehensive systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Olfactory dysfunction is a common manifestation in COVID-19 patients and can significantly impact their quality of life. Corticosteroids have been proposed as a potential treatment, but their efficacy remains controversial. This systematic review and meta-analysis aims to comprehensively analyze the efficacy of corticosteroid therapy for treating COVID-19-related olfactory dysfunction.

METHODS

A literature search was conducted in PubMed, Cochrane Library, and Embase databases up to March 1, 2023. Randomized controlled trials investigating the effects of corticosteroids on olfactory dysfunction in patients with COVID-19 were included. The primary outcome was the olfactory score at the end of follow-up, and the secondary outcomes were the duration and the rate of recovery from olfactory dysfunction.

RESULTS

Seven randomized controlled trials with 999 participants were included in the meta-analysis. Compared with the control group, corticosteroid treatment resulted in a statistically significant improvement in olfactory score with a standardized mean difference of 0.55 (95% CI: 0.15 to 0.95). Topical corticosteroids were found to be effective, but systemic corticosteroids were not. In addition, longer durations and higher dosages of corticosteroids treatment may also be associated with significant improvements in olfactory scores. No significant effect was observed on the duration or recovery rate of olfactory dysfunction.

CONCLUSIONS

Our findings suggest that topical corticosteroid treatment is a viable option for improving COVID-19-related olfactory dysfunction, but further research is needed to investigate optimal treatment protocols and safety profiles.

Olfactory recovery following omicron variant infection: a psychophysical prospective case-control study with six-month follow up

OBJECTIVE

This study aimed to evaluate the recovery of olfactory function at six months in individuals infected with the coronavirus disease 2019 omicron variant, using psychophysical tests.

METHODS

A prospective case-control study that included severe acute respiratory syndrome coronavirus-2 patients infected in February and March 2022 was conducted. Patients underwent the Sniffin' Sticks test within 10 days of infection and again after at least 6 months. The olfactory scores were compared with those of a control group.

RESULTS

In all, 102 patients and 120 controls were enrolled in the study. At baseline, 26 patients (25.5 per cent) self-reported smell loss. The median threshold, discrimination and identification score was 33.6 (interquartile range, 12.5) for the cases and 36.5 (interquartile range, 4.38) for the controls (p < 0.001). Based on the threshold, discrimination and identification scores, 12 controls and 34 patients reported olfactory dysfunction (p < 0.001). Eighty cases underwent re-evaluation at six months; the median threshold, discrimination and identification score was 37.1 (interquartile range, 4.75) with no significant differences compared with the controls.

CONCLUSION

Six months after infection, the prevalence of olfactory dysfunction in patients did not differ significantly from the control population.

Development and Validation of the Parosmia Olfactory Dysfunction Outcomes Rating (DisODOR)

OBJECTIVE

Develop and validate a quality-of-life (QoL) outcome measure for patients with dysosmia.

STUDY DESIGN

Cross-sectional survey study.

SETTING

Otolaryngology clinics, research registries, and Facebook support groups.

METHODS

A 59-item pilot survey with questions addressing parosmia concerns was developed using input from subjects with parosmia and clinical expertise from Otolaryngologists. After item reduction, the Parosmia Olfactory Dysfunction Outcomes Rating (DisODOR) was reduced to its final 29 items. DisODOR maximum score is 116 (each item score 0-4) with higher scores indicating a higher degree of dysfunction from smell distortion. DisODOR was validated using participants with parosmia persisting >3 months after severe acute respiratory syndrome coronavirus 2 (cases) and healthy controls. Reliability, face and content validity, internal consistency, convergent validity, discriminative validity, sensitivity to change, and the minimal clinically important difference (MCID) were assessed.

RESULTS

A total of 134 cases and 20 controls completed DisODOR. The mean (SD) age was 45.9 (12.2) for cases and 29.6 (8.9) for controls. The mean score difference between cases and controls was 45.0 (95% confidence interval, 40.5-49.5) displaying good discriminative validity. DisODOR showed strong test-retest reliability (r = .942) with high internal consistency (Cronbach's α = .971). DisODOR had a moderate correlation with SNOT-22 scores (r = .619) indicating good convergent validity. There is an excellent association with the global impression of severity categories (η2  = 0.447). Based on the distribution method, the MCID is 15.

CONCLUSION

DisODOR is a valid, reliable QoL instrument for parosmia that can be used to measure the functional impact and QoL impairment for parosmia patients. DisODOR is sensitive to change and thus can be used in studies investigating treatments for parosmia.

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.

Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological manifestations. Utilizing a systematic review, this study aims to summarize brain MRI findings in COVID-19 patients presenting with neurological symptoms.

METHODS

Systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched for literature addressing brain MRI findings in COVID-19 patients with neurological symptoms.

RESULTS

25 publications containing a total number of 3118 COVID-19 patients with neurological symptoms who underwent MRI were included. The most common MRI findings and the respective pooled incidences in decreasing order were acute/subacute infarct (22%), olfactory bulb abnormalities (22%), white matter abnormalities (20%), cerebral microbleeds (17%), grey matter abnormalities (12%), leptomeningeal enhancement (10%), ADEM (Acute Disseminated Encephalomyelitis) or ADEM-like lesions (10%), non-traumatic ICH (10%), cranial neuropathy (8%), cortical gray matter signal changes compatible with encephalitis (8%), basal ganglia abnormalities (5%), PRES (Posterior Reversible Encephalopathy Syndrome) (3%), hypoxic-ischemic lesions (4%), venous thrombosis (2%), and cytotoxic lesions of the corpus callosum (2%).

CONCLUSION

The present study revealed that a considerable proportion of patients with COVID-19 might harbor neurological abnormalities detectable by MRI. Among various findings, the most common MRI alterations are acute/subacute infarction, olfactory bulb abnormalities, white matter abnormalities, and cerebral microbleeds.

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.

Distinct smell and taste disorder phenotype of post-acute COVID-19 sequelae

PURPOSE

Olfactory dysfunction (OD) commonly accompanies coronavirus disease 2019 (COVID-19). We investigated the kinetics of OD resolution following SARS-CoV-2 infection (wild-type and alpha variant) and its impact on quality of life, physical and mental health.

METHODS

OD prevalence was assessed in an ambulatory COVID-19 survey (n = 906, ≥ 90 days follow-up) and an observational cohort of ambulatory and hospitalized individuals (n = 108, 360 days follow-up). Co-occurrence of OD with other symptoms and effects on quality of life, physical and mental health were analyzed by multi-dimensional scaling, association rule mining and semi-supervised clustering.

RESULTS

Both in the ambulatory COVID-19 survey study (72%) and the observational ambulatory and hospitalized cohort (41%) self-reported OD was frequent during acute COVID-19. Recovery from self-reported OD was slow (survey: median 28 days, observational cohort: 90 days). By clustering of the survey data, we identified a predominantly young, female, comorbidity-free group of convalescents with persistent OD and taste disorders (median recovery: 90 days) but low frequency of post-acute fatigue, respiratory or neurocognitive symptoms. This smell and taste disorder cluster was characterized by a high rating of physical performance, mental health, and quality of life as compared with convalescents affected by prolonged fatigue or neurocognitive complaints.

CONCLUSION

Our results underline the heterogeneity of post-acute COVID-19 sequelae calling for tailored management strategies. The persistent smell and taste disorder phenotype is characterized by good clinical, physical, and mental recovery and may pose a minor challenge for public health.

STUDY REGISTRATION

ClinicalTrials.gov: NCT04661462 (survey study), NCT04416100 (observational cohort).

Olfactory disorders in childhood: A comparative study of olfaction in children with adenoid hyperplasia versus a control group and the postoperative effects of adenoidectomy with respect to olfactory ability

PURPOSE

Hyposmia in childhood is poorly characterized. The "U-Sniff Test", validated for children with anosmia, can be used to objectify olfactory impairment but has not been used to distinguish between hyposmia and normosmia. Therefore, we investigated children with enlarged adenoids with respect to hyposmia, its correlation with adenoid size, and the sensitivity of questionnaires to predict olfactory impairment.

METHODS

In a prospective comparison, olfaction was assessed by "U-Sniff Test" (score 0-12; <8 hyposmia) in 41 children (5-18 years) with adenoid hyperplasia and compared with 196 children without any respiratory affection (control) after exclusion of previous SARS-Cov2-infection from December 2020 to December 2021. ENT-related complaints were collected using a self-designed questionnaire. We were able to include 13 children in a follow-up examination to compare preoperative performance in the "U-Sniff Test" with postoperative outcome after adenoidectomy.

STATISTICS

chi-square-test (p < 0.05), odds-ratio, Spearman's rho, ROC-, cluster analysis.

RESULTS

Severe hyposmia was present in 36.6% of children with adenoid-hyperplasia compared to 3.1% of the control-group. Adenoid-children scored significantly more often between 8 and 10 points (58.5%) than the control (31.6%; p < 0.01). Adenoid size and olfactory performance correlate significantly (r: 0.83; CI -0.89 … -0.72). Hyposmia in the adenoid group is characterized predominately by loss of the odors banana, butter and rose. None of children with hyposmia or parents reported impaired olfactory performance. Postoperatively, olfactory function improved significantly in 85% of cases (p 0.01, SD ± 1.71, Δ3.54points).

CONCLUSION

Questionnaires are insufficient to detect hyposmia in this cohort. In contrast, the "U-Sniff Test" detects even reduced olfactory performance without reaching the cut-off value, which represents the majority of test results in the adenoid group. Therefore, we recommend the classification of moderate hyposmia (8-10 points) to be included for our study population.

Orthonasal and retronasal odor identification in patients with parosmia

OBJECTIVE

To compare retronasal and orthonasal perception in parosmic COVID-19 patients, in order to determine whether COVID-19 has a differential effect on these functions.

METHODS

Using the Sniffin Sticks test battery orthonasal function was examined for odor threshold, discrimination and identification. Retronasal function was assessed using 20 tasteless aromatized powders. Gustatory function was measured using the Taste Strips test.

RESULTS

This study included 177 patients (127 women, 50 men; mean age 45 years), of whom 127 (72%) were hyposmic and 50 (28%) normosmic. Compared to patients without parosmia, parosmic patients performed worse in odor identification for both orthonasal (F = 4.94, p = 0.03) and retronasal tests (F = 11.95, p < 0.01). However, an interaction effect between route of odor identification (orthonasal or retronasal) and parosmia status was found (F = 4.67, p = 0.03): patients with parosmia had relatively lower retronasal scores than patients without parosmia.

CONCLUSION

Our results suggest that COVID-19 may affect the olfactory mucosa differently along the anterior-posterior axis, thereby possibly contributing to the pathophysiology of parosmia. Patients with parosmia also exhibit a higher degree of impairment when odors are presented through the retronasal route during eating and drinking.

BMI Increases in Individuals with COVID-19-Associated Olfactory Dysfunction

(1) Background: Reports suggest COVID-19-associated olfactory dysfunction (OD) may result in alterations in dietary behaviors and perceived weight change, but few studies using psychophysical evaluation of post-COVID-19-associated chemosensory dysfunction and body mass index (BMI) exist. The purpose of this study is to assess the impact of both quantitative and qualitative features of COVID-19-associated OD on BMI; (2) Methods: Recruitment of thirty-one participants with self-reported OD in the form of quantitative loss with and without qualitative features. Surveys with questions specific to qualitative olfactory function, Sniffin' Sticks tests, and BMI measures were completed at two visits, one year apart. Group differences were assessed with Wilcoxon signed-rank tests and the Holm-Bonferroni method; (3) Results: Individuals with persistent quantitative OD (n = 15) and self-reported parosmia (n = 19) showed statistically significant increases in BMI after 1 year (p = 0.004, adjusted α = 0.0125; p = 0.011, adjusted α = 0.0167). Controls with transient quantitative OD (n = 16) and participants without self-reported parosmia (n = 12) showed no statistically significant changes in BMI over the same time period (p = 0.079, adjusted α = 0.05; p = 0.028, adjusted α = 0.025); (4) Conclusions: This study shows an association between COVID-19-associated OD and BMI, suggesting olfaction may play a role in altering dietary habits and nutrition in this population. Larger study cohorts are needed to further evaluate this relationship.

Immune landscape and redox imbalance during neurological disorders in COVID-19

The outbreak of Coronavirus Disease 2019 (COVID-19) has prompted the scientific community to explore potential treatments or vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes the illness. While SARS-CoV-2 is mostly considered a respiratory pathogen, several neurological complications have been reported, raising questions about how it may enter the Central Nervous System (CNS). Receptors such as ACE2, CD147, TMPRSS2, and NRP1 have been identified in brain cells and may be involved in facilitating SARS-CoV-2 entry into the CNS. Moreover, proteins like P2X7 and Panx-1 may contribute to the pathogenesis of COVID-19. Additionally, the role of the immune system in the gravity of COVID-19 has been investigated with respect to both innate and adaptive immune responses caused by SARS-CoV-2 infection, which can lead to a cytokine storm, tissue damage, and neurological manifestations. A redox imbalance has also been linked to the pathogenesis of COVID-19, potentially causing mitochondrial dysfunction, and generating proinflammatory cytokines. This review summarizes different mechanisms of reactive oxygen species and neuro-inflammation that may contribute to the development of severe COVID-19, and recent progress in the study of immunological events and redox imbalance in neurological complications of COVID-19, and the role of bioinformatics in the study of neurological implications of COVID-19.

Post-viral olfactory loss and parosmia

The emergence of SARS-CoV-2 has brought olfactory dysfunction to the forefront of public awareness, because up to half of infected individuals could develop olfactory dysfunction. Loss of smell-which can be partial or total-in itself is debilitating, but the distortion of sense of smell (parosmia) that can occur as a consequence of a viral upper respiratory tract infection (either alongside a reduction in sense of smell or as a solo symptom) can be very distressing for patients. Incidence of olfactory loss after SARS-CoV-2 infection has been estimated by meta-analysis to be around 50%, with more than one in three who will subsequently report parosmia. While early loss of sense of smell is thought to be due to infection of the supporting cells of the olfactory epithelium, the underlying mechanisms of persistant loss and parosmia remain less clear. Depletion of olfactory sensory neurones, chronic inflammatory infiltrates, and downregulation of receptor expression are thought to contribute. There are few effective therapeutic options, so support and olfactory training are essential. Further research is required before strong recommendations can be made to support treatment with steroids, supplements, or interventions applied topically or injected into the olfactory epithelium in terms of improving recovery of quantitative olfactory function. It is not yet known whether these treatments will also achieve comparable improvements in parosmia. This article aims to contextualise parosmia in the setting of post-viral olfactory dysfunction, explore some of the putative molecular mechanisms, and review some of the treatment options available.

The immune mechanism of the nasal epithelium in COVID-19-related olfactory dysfunction

During the first waves of the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, olfactory dysfunction (OD) was reported as a frequent clinical sign. The nasal epithelium is one of the front-line protections against viral infections, and the immune responses of the nasal mucosa may be associated with OD. Two mechanisms underlying OD occurrence in COVID-19 have been proposed: the infection of sustentacular cells and the inflammatory reaction of the nasal epithelium. The former triggers OD and the latter likely prolongs OD. These two alternative mechanisms may act in parallel; the infection of sustentacular cells is more important for OD occurrence because sustentacular cells are more likely to be the entry point of SARS-CoV-2 than olfactory neurons and more susceptible to early injury. Furthermore, sustentacular cells abundantly express transmembrane protease, serine 2 (TMPRSS2) and play a major role in the olfactory epithelium. OD occurrence in COVID-19 has revealed crucial roles of sustentacular cells. This review aims to elucidate how immune responses of the nasal epithelium contribute to COVID-19-related OD. Understanding the underlying immune mechanisms of the nasal epithelium in OD may aid in the development of improved medical treatments for COVID-19-related OD.

[S1 guidelines for the management of postviral conditions using the example of post-COVID-19]

These S1 guidelines are an updated and expanded version of the S1 guidelines on long COVID differential diagnostic and management strategies. They summarize the state of knowledge on postviral conditions like long/post COVID at the time of writing. Due to the dynamic nature of knowledge development, they are intended to be "living guidelines". The focus is on practical applicability at the level of primary care, which is understood to be the appropriate place for initial access and for primary care and treatment. The guidelines provide recommendations on the course of treatment, differential diagnostics of the most common symptoms that can result from infections like with SARS-CoV-2, treatment options, patient management and care, reintegration and rehabilitation. The guidelines have been developed through an interdisciplinary and interprofessional process and provide recommendations on interfaces and possibilities for collaboration.

Neurologic Complications of COVID-19

OBJECTIVE

This article describes the spectrum of neurologic complications occurring in acute or postacute infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as the neurologic risks and benefits of vaccination against SARS-CoV-2.

LATEST DEVELOPMENTS

Early in the COVID-19 pandemic, reports of neurologic complications of COVID-19 began to surface. A variety of neurologic conditions have since been reported in association with COVID-19. Understanding of the underlying mechanism of COVID-19 neurologic involvement continues to evolve; however, the evidence seems to suggest that aberrant inflammatory responses may play a role. In addition to neurologic symptoms in acute COVID-19, neurologic post-COVID-19 conditions are increasingly recognized. The development of COVID-19 vaccines has been essential in preventing the spread of COVID-19. With increasing numbers of vaccine doses administered, various neurologic adverse events have been reported.

ESSENTIAL POINTS

Neurologists must be aware of the potential acute, postacute, and vaccine-associated neurologic complications associated with COVID-19 and be poised to serve as integral members of multidisciplinary care teams for patients with COVID-19-related conditions.

Persistent olfactory dysfunction in mild COVID-19 patients: A descriptive study of the characteristics and association with other symptoms

Introduction

Post-COVID olfactory dysfunction continues to be studied due to the controversy of the mechanisms involved. The aim was to investigate the olfactory dysfunctions in association with other post-COVID symptoms.

Material and methods

Observational, descriptive and single-center study. The patients had confirmed mild COVID-19 and subjective olfactory dysfunction of more than a month of evolution, which was assessed by Sniffin' Sticks Olfactory Test.

Results

A total of 86 patients participated. The mean age was 37.2 years (SD 9.82). 70.9% reported parosmia and 46.5% symptoms of brain fog. A pathological test result was obtained in 72.1% of the participants. The most failed pen was 11 (apple) in 76.7%. Anosmia of pen 15 (anise) was reported more frequently in 24.4% and cacosmia of pen 9 (garlic) in 27.9%. We observed a significant association between patients who reported parosmias and brain fog (RR 2.18; p = 0.018), also between parosmia and phantosmia (RR 6.042; p < 0.001).

Conclusion

There is some pathological selectivity for certain test pens, a higher prevalence of cognitive symptoms and many patients with combined parosmia and brain fog.

COVID-19 olfactory dysfunction, evaluation of onset, and persistence

Olfactory dysfunction (OD) is a common feature of COVID-19. The goal of the study was to define the modes of onset of OD in the clinical course of the disease and to follow the cases for 12-18 months in order to estimate the differences in the recovery time from OD over the course of the disease. We managed to follow a total of 325 patients (females: 198, males: 127) in the Babylon governorate in Iraq. All were COVID-19 patients who should have OD during the course of the disease. COVID-19 infection was established in all patients by swab test, i.e. polymerase chain reaction (PCR) and/or chest computed tomography findings of pneumonia compatible with COVID-19. Detailed medical records were obtained directly from the patients or their relatives. The patients were then followed up by telephone and questioned with structured questionnaires concentrating upon general clinical features and the sense of olfaction. Information about the presence of olfactory disorders, their occurrence, and development was recorded. Based on the onset of OD, the patients were categorized into three groups. Olfactory functions were assessed primarily by face-to-face interview and then (if necessary) by a telephone questionnaire assessing self-reported olfactory function and olfactory-related quality of life, which measures the subjective olfactory capability (SOC). In the first 2 weeks, 148 (45.5%) patients reported complete recovery from OD, of which 90 (73.2%) patients joined at the end of the 1st month. OD persistence was observed in 11 (3.3%) patients toward the end of the 1st year, in 5 (1.5%) patients at the end of the 15th month, and only in two (0.6%) patients at the end of the 18th month. We found no significant correlation between the type of onset of OD and the duration and persistence of OD. Most sufferers of COVID-associated OD recover their sense of smell within the 1st month.

Clinical and Imaging Evaluation of COVID-19-Related Olfactory Dysfunction

BACKGROUND

Olfactory dysfunction has been reported in 47.85% of COVID patients. It can be broadly categorized into conductive or sensorineural olfactory loss. Conductive loss occurs due to impaired nasal air flow, while sensorineural loss implies dysfunction of the olfactory epithelium or central olfactory pathways.

OBJECTIVES

The aim of this study was to analyze the clinical and imaging findings in patients with COVID-related olfactory dysfunction. Additionally, the study aimed to investigate the possible mechanisms of COVID-related olfactory dysfunction.

METHODS

The study included 110 patients with post-COVID-19 olfactory dysfunction, and a control group of 50 COVID-negative subjects with normal olfactory function. Endoscopic nasal examination was performed for all participants with special focus on the olfactory cleft. Smell testing was performed for all participants by using a smell diskettes test. Olfactory pathway magnetic resonance imaging (MRI) was done to assess the condition of the olfactory cleft and the dimensions and volume of the olfactory bulb.

RESULTS

Olfactory dysfunction was not associated with nasal symptoms in 51.8% of patients. MRI showed significantly increased olfactory bulb dimensions and volume competed to controls. Additionally, it revealed olfactory cleft edema in 57.3% of patients. On the other hand, radiological evidence of sinusitis was detected in only 15.5% of patients.

CONCLUSION

The average olfactory bulb volumes were significantly higher in the patients' group compared to the control group, indicating significant edema and swelling in the olfactory bulb in patients with COVID-related olfactory dysfunction. Furthermore, in most patients, no sinonasal symptoms such as nasal congestion or rhinorrhea were reported, and similarly, no radiological evidence of sinusitis was detected. Consequently, the most probable mechanism of COVID-related olfactory dysfunction is sensorineural loss through virus spread and damage to the olfactory epithelium and pathways.

Visual Analogue Scale for the Evaluation of Olfactory and Gustatory Dysfunction of COVID-19 Patients in Northwestern Greece

Background The visual analogue scale (VAS) has been used as a diagnostic tool for the evaluation of the severity of olfactory and gustatory dysfunction (OGD) caused by SARS-CoV2 infection. The main objective of the present study was the evaluation of OGD with VAS in COVID-19-positive patients in Northwestern Greece and its possible association with the patients' self-reported symptoms of olfactory and gustatory dysfunction. Methods The presence of olfactory and gustatory symptoms and their severity were assessed by questionnaire along with the use of specific odorants and tastant ingredients, in three time periods: prior to COVID-19, during COVID-19 (initial diagnosis) and post-COVID-19 disease (at four weeks from disease onset). Three hundred COVID-19-positive patients (home-quarantined and hospitalized) tested with RT-PCR test in the University Hospital of Ioannina Greece were included in this study. Statistical analysis was performed on SPSS Statistics 26.0 (IBM Corp., Armonk, NY) Results Out of a total of 300 patients, 146 and 190 patients had mild hyposmia and hypogeusia respectively, followed by patients with severe hyposmia or hypogeusia (118 and 88 respectively), at the time of COVID-19 onset (initial diagnosis). An increase in the number of patients with recovery of symptoms was observed during the follow-up period, during which only eight patients had non-resolving severe symptoms (six patients with hyposmia and two with hypogeusia). On further analysis, a statistically significant association was found between the severity of symptoms (assessed by VAS score) and the self-reported symptoms of sensory dysfunction by the patients. There was a significant association between the groups of patients with mild hyposmia and patients that reported no loss of smell; between the patients with moderate hyposmia and the patients who reported "loss of smell"; and between the patients with severe hyposmia and the group of patients who reported a loss of smell, at the COVID-19 onset period. Similarly, patients with mild hyposmia were associated with those that reported a loss of smell at the same time. The severity of hyposmia was also associated with the reported symptom of "loss of taste" at the time of COVID-19 diagnosis. Similar findings were observed regarding the severity of hypogeusia and the reported symptom of "loss of taste" among the groups of patients. Finally, the severity of hypogeusia was associated with smell loss at the time of initial diagnosis of the infection. Conclusion Similar to the literature data, our findings indicate that hyposmia and hypogeusia are common symptoms of COVID-19 disease with varying severity. In our study, most of the patients exerted a complete recovery of these OGD symptoms. In addition, we found an association between olfactory dysfunction and self-reported sensory of taste as well as gustatory dysfunction and sensory of smell. Finally, we found that the VAS score was a reliable diagnostic tool in the estimation of OGD in this cohort of patients. However, our results need to be confirmed by larger-scale trials.

Anti-cancer effect of COVID-19 vaccines in 4T1 mice models

AIMS

Without any doubt, vaccination was the best choice for Coronavirus disease 2019 (COVID-19) pandemic control. According to the American Society of Clinical Oncology (ASCO) and European Society for Medical Oncology (ESMO), people with cancer or a history of cancer have a higher risk of dying from Covid-19 than ordinary people; hence, they should be considered a high-priority group for vaccination. On the other hand, the effect of the Covid-19 vaccination on cancer is not transparent enough. This study is one of the first in vivo studies that try to show the impact of Sinopharm (S) and AstraZeneca (A) vaccines on breast cancer, the most common cancer among women worldwide.

MATERIALS AND METHODS

Vaccination was performed with one and two doses of Sinopharm (S1/S2) or AstraZeneca (A1/A2) on the 4T1 triple-negative breast cancer (TNBC) mice model. The tumor size and body weight of mice were monitored every two days. After one month, mice were euthanized, and the existence of Tumor-infiltrating lymphocytes (TILs) and expression of the important markers in the tumor site was assessed. Metastasis in the vital organs was also investigated.

KEY FINDINGS

Strikingly, all of the vaccinated mice showed a decrease in tumor size and this decrease was highest after two vaccinations. Moreover, we observed more TILs in the tumor after vaccination. Vaccinated mice demonstrated a decrease in the expression of tumor markers (VEGF, Ki-67, MMP-2/9), CD4/CD8 ratio, and metastasis to the vital organs.

SIGNIFICANCE

Our results strongly suggest that COVID-19 vaccinations decrease tumor growth and metastasis.

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.

SARS-CoV-2 Effects on Psychophysical Olfactory Scores: Prospective Study With Evaluation Before and 60-Days After Infection

The aim of this study was to prospectively evaluate the olfactory function in a series of individuals infected with SARS-CoV-2 and who had undergone psychophysical olfactory assessment prior to infection. Individuals unexposed to SARS-CoV-2 infection underwent a psychophysical evaluation of smell with the Sniffin' Sticks test. The subjects were followed prospectively and included in the study if they developed SARS-CoV-2 infection with a second test 60 days after recovery. At the 60-day follow-up of the 41 included subjects, 2 (4.9%) self-reported persistent olfactory dysfunction (OD). The differences between TDI scores before and after infection were statistically significant (37 [interquartile range (IQR), 34.25-39.25] vs 34.75 [IQR, 32.25-38]; p = .021). Analyzing the individual olfactory domains, the differences were significant for threshold (T) (9.75 [IQR, 9-11.25] vs 8.25 [IQR, 7.25-10.25]; p = .009) but not for odor discrimination (D) (p = .443) and identification (I) (p = .159). SARS-CoV-2 causes a significant reduction in the olfactory function, in particular affecting the olfactory threshold, even in subjects who do not self-report an OD.

Olfactory impairment in patients with coronavirus disease 2019 self-perceived as asymptomatic

BACKGROUND

Olfactory impairment may be present among patients with coronavirus disease 2019 self-perceived as asymptomatic. This study aimed to assess olfactory function among these individuals.

METHODS

A cross-sectional study involving patients with coronavirus disease 2019 self-perceived as asymptomatic was conducted. Assessments included the subjective Malaysian Smell and Taste Questionnaire and the culturally adapted Malaysian version of the objective Sniffin' Sticks Identification smell test.

RESULTS

In 81 participants (mean age of 31.59 ± 12.04 years), with mean time from diagnosis to smell test of 7.47 ± 3.79 days, subjective assessment showed that 80.2 per cent were asymptomatic (questionnaire score of 6) and 19 per cent had mild symptoms (questionnaire score of 7 and 8). The mean objective smell test score was 10.89 ± 2.11. The prevalence of olfactory impairment was 76.6 per cent among patients with coronavirus disease 2019 self-perceived as asymptomatic. There was no association between the questionnaire and the smell test scores (p = 0.25). There was a correlation between the smell test score and the duration from diagnosis to smell test (p = 0.04).

CONCLUSION

The objective assessment demonstrated that coronavirus disease 2019 patients who perceived themselves as asymptomatic showed olfactory impairment.

Heat stroke management during the COVID-19 pandemic: Recommendations from the experts in Japan (2nd edition)

Both coronavirus disease 2019 (COVID-19) and heat stroke have symptoms of fever or hyperthermia and the difficulty in distinguishing them could lead to a strain on emergency medical care. To mitigate the potential confusion that could arise from actions for preventing both COVID-19 spread and heat stroke, particularly in the context of record-breaking summer season temperatures, this work offers new knowledge and evidence that address concerns regarding indoor ventilation and indoor temperatures, mask wearing and heat stroke risk, and the isolation of older adults. Specifically, the current work is the second edition to the previously published guidance for handling heat stroke during the COVID-19 pandemic, prepared by the "Working group on heat stroke medical care during the COVID-19 epidemic," composed of members from four organizations in different medical and related fields. The group was established by the Japanese Association for Acute Medicine Heatstroke and Hypothermia Surveillance Committee. This second edition includes new knowledge, and conventional evidence gleaned from a primary selection of 60 articles from MEDLINE, one article from Cochrane, 13 articles from Ichushi, and a secondary/final selection of 56 articles. This work summarizes the contents that have been clarified in the prevention and treatment of infectious diseases and heat stroke to provide guidance for the prevention, diagnosis, and treatment of heat stroke during the COVID-19 pandemic.

The COVID-19 Pandemic: SARS-CoV-2 Structure, Infection, Transmission, Symptomology, and Variants of Concern

Since it was first detected in December 2019, the COVID-19 pandemic has spread across the world and affected virtually every country and territory. The pathogen driving this pandemic is SARS-CoV-2, a positive-sense single-stranded RNA virus which is primarily transmissible though the air and can cause mild to severe respiratory infections in humans. Within the first year of the pandemic, the situation worsened with the emergence of several SARS-CoV-2 variants. Some of these were observed to be more virulent with varying capacities to escape the existing vaccines and were, therefore, denoted as variants of concern. This chapter provides a general overview of the course of the COVID-19 pandemic up to April 2022 with a focus on the structure, infection, transmission, and symptomology of the SARS-CoV-2 virus. The main objectives were to investigate the effects of the variants of concern on the trajectory of the virus and to highlight a potential pathway for coping with the current and future pandemics.

Persistent olfactory dysfunction in mild COVID-19 patients: A descriptive study of the characteristics and association with other symptoms

INTRODUCTION

Post-COVID olfactory dysfunction continues to be studied due to the controversy of the mechanisms involved. The aim was to investigate the olfactory dysfunctions in association with other post-COVID symptoms.

MATERIAL AND METHODS

Observational, descriptive and single-center study. The patients had confirmed mild COVID-19 and subjective olfactory dysfunction of more than a month of evolution, which was assessed by Sniffin' Sticks Olfactory Test.

RESULTS

A total of 86 patients participated. The mean age was 37.2 years (SD 9.82). 70.9% reported parosmia and 46.5% symptoms of brain fog. A pathological test result was obtained in 72.1% of the participants. The most failed pen was 11 (apple) in 76.7%. Anosmia of pen 15 (anise) was reported more frequently in 24.4% and cacosmia of pen 9 (garlic) in 27.9%. We observed a significant association between patients who reported parosmias and brain fog (RR 2.18; p=0.018), also between parosmia and phantosmia (RR 6.042; p<0.001).

CONCLUSION

There is some pathological selectivity for certain test pens, a higher prevalence of cognitive symptoms and many patients with combined parosmia and brain fog.

Parosmia as a predictor of a better olfactory function in COVID-19: a multicentric longitudinal study for upper respiratory tract infections

PURPOSE

This study aimed to evaluate the course of olfactory dysfunction [OD] due to upper respiratory tract infections [URTI] especially for COVID-19 [C19] in a multicentric design and to investigate possible predictors for the outcome.

METHODS

In a multicentric study, patients (n = 147, of which 96 were women) with OD due to URTI, including C19 and non-C19 were evaluated at two visits with a standardized medical history and "Sniffin' Sticks" extended psychophysical testing to examine the course and possible predictors for improvement of olfactory function.

RESULTS

C19 patients showed better overall olfactory function (p < 0.001) compared to non-C19. Olfactory function (p < 0.001) improved over 3.5 ± 1.2 months in a comparable fashion for C19 and non-C19 comparable over time (p = 0.20) except for a more pronounced improvement of odour threshold (p = 0.03) in C19. C19 patients with parosmia exhibited a higher probability of clinically relevant improvement of odour threshold, a better threshold in the second visit, and tended to have a better TDI-score at the second visit. Further possible predictors for an improving olfactory function were younger age, female gender, and had lower scores in olfactory tests at the first visit.

CONCLUSIONS

Patients with C19 and non-C19 URTI exhibit a similar improvement over 3-4 months except for the odour threshold, with a better TDI in both visits for C19. For C19 a better prognosis in terms of olfactory recovery was found for younger patients with parosmia and lower olfactory scores at the first visit. Still, for many patients with olfactory loss, an improvement that is experienced as complete may only occur over months and possibly years.

The Trajectories of Olfactory Dysfunction from the First to the Omicron Wave: Are We Getting over it?

It has now been two years since the publication in Pathogens of our European multicenter study on the prevalence of olfactory dysfunctions (OD) during COVID-19 [...].

Structural brain changes in post-acute COVID-19 patients with persistent olfactory dysfunction

OBJECTIVE

This research aims to study structural brain changes in patients with persistent olfactory dysfunctions after coronavirus disease 2019 (COVID-19).

METHODS

COVID-19 patients were evaluated using T1-weighted and diffusion tensor imaging (DTI) on a 3T MRI scanner, 9.94 ± 3.83 months after COVID-19 diagnosis. Gray matter (GM) voxel-based morphometry was performed using FSL-VBM. Voxelwise statistical analysis of the fractional anisotropy, mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity was carried out with the tract-based spatial statistics in the olfactory system. The smell identification test (UPSIT) was used to classify patients as normal olfaction or olfactory dysfunction groups. Intergroup comparisons between GM and DTI measures were computed, as well as correlations with the UPSIT scores.

RESULTS

Forty-eight COVID-19 patients were included in the study. Twenty-three were classified as olfactory dysfunction, and 25 as normal olfaction. The olfactory dysfunction group had lower GM volume in a cluster involving the left amygdala, insular cortex, parahippocampal gyrus, frontal superior and inferior orbital gyri, gyrus rectus, olfactory cortex, caudate, and putamen. This group also showed higher MD values in the genu of the corpus callosum, the orbitofrontal area, the anterior thalamic radiation, and the forceps minor; and higher RD values in the anterior corona radiata, the genu of the corpus callosum, and uncinate fasciculus compared with the normal olfaction group. The UPSIT scores for the whole sample were negatively associated with both MD and RD values (p-value ≤0.05 FWE-corrected).

INTERPRETATION

There is decreased GM volume and increased MD in olfactory-related regions explaining prolonged olfactory deficits in post-acute COVID-19 patients.

The Clinical Significance of Otolaryngology Manifestations in COVID-19 Pneumonia: A Single-center Retrospective Cohort Study

Objective Although the absence of a runny nose and sore throat, both ear-nose-throat (ENT) symptoms, suggests community-acquired pneumonia (CAP), the association between ENT symptoms and coronavirus disease 2019 (COVID-19) pneumonia remains unclear. We therefore investigated the association between ENT symptoms and COVID-19 pneumonia. Methods We retrospectively recruited consecutive confirmed COVID-19 inpatients with and without pneumonia admitted to a single institution from April 1, 2020, to July 31, 2021. After a descriptive analysis, we implemented univariable and multivariable regression analyses to assess the association between ENT symptoms and COVID-19 pneumonia. Results The present study included 385 patients. Pneumonia patients exhibited lower rates of positive runny nose and sore throat than non-pneumonia patients. Univariable analyses found mean odds ratios of 0.59 and 0.61 and 95% confidence intervals (CIs) of 0.30-1.16 and 0.32-1.17 for runny nose and sore throat, respectively, and multivariable analyses found mean odds ratios of 0.73 and 0.70 and 95% CIs of 0.34-1.56 and 0.34-1.46, respectively. Conclusion Our study found no statistically significant association between ENT symptoms and COVID-19 pneumonia. Clinicians should be aware that, unlike CAP, there is no correlation between ENT symptoms and pneumonia among patients with COVID-19, so it is necessary to consider the possibility of pneumonia even in the presence of ENT symptoms.

Neurological consequences of COVID-19

In December 2019, cases of pneumonia caused by infection with the previously unknown severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to coronavirus disease 2019 (COVID-19), were identified. Typical manifestations of COVID-19 are fever, cough, fatigue and dyspnoea. Initially, it was thought that the mechanism of action of SARS-CoV-2 was only associated with respiratory tract invasion, but it was later revealed that the infection might involve many other organs and systems, including the central and peripheral nervous systems. Neurological complications associated with SARS-CoV-2 infection include encephalopathy, encephalitis, meningitis, acute disseminated encephalomyelitis (ADEM), ischaemic and haemorrhagic stroke and cerebral venous sinus thrombosis. In cases of peripheral nervous system involvement, smell and taste disorders, myopathy or the signs and symptoms of Guillain‒Barré syndrome are observed. The most common early neurological complications, particularly during the first year of the epidemic, were anosmia and taste disorders, which, according to some studies, occurred in over 80 percent of patients with COVID-19. The proportion of patients with serious neurological manifestations was small compared to the global number of patients, but the numbers of SARS-CoV-2 infections and critical patients increased substantially. The experience from 2 years of the pandemic has shown that approximately 13% of infected patients suffer from severe neurological complications. The relationship between SARS-CoV-2 and the nervous system is not only a cause of neurological complications in previously healthy individuals but also directly and indirectly affects the courses of many nervous system diseases.

Progress on COVID-19 Chemotherapeutics Discovery and Novel Technology

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel highly contagious and pathogenic coronavirus that emerged in late 2019. SARS-CoV-2 spreads primarily through virus-containing droplets and small particles of air pollution, which greatly increases the risk of inhaling these virus particles when people are in close proximity. COVID-19 is spreading across the world, and the COVID-19 pandemic poses a threat to human health and public safety. To date, there are no specific vaccines or effective drugs against SARS-CoV-2. In this review, we focus on the enzyme targets of the virus and host that may be critical for the discovery of chemical compounds and natural products as antiviral drugs, and describe the development of potential antiviral drugs in the preclinical and clinical stages. At the same time, we summarize novel emerging technologies applied to the research on new drug development and the pathological mechanisms of COVID-19.