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Ear, Nose, & Throat Journal May 2024The pandemic has affected over 182 million coronavirus disease 2019 (COVID-19) cases worldwide. Accumulated evidence indicates that anosmia is one of the significant... (Review)
Review
OBJECTIVES
The pandemic has affected over 182 million coronavirus disease 2019 (COVID-19) cases worldwide. Accumulated evidence indicates that anosmia is one of the significant characteristics of COVID-19 with a high prevalence. However, many aspects of COVID-19-induced anosmia are still far from being fully understood. The purpose of this review is to summarize recent developments in COVID-19-induced anosmia to increase awareness of the condition.
METHODS
A literature search was carried out using the PubMed, Embase, Web of Science, and Scopus. We reviewed the latest literature on COVID-19-induced anosmia, including mechanisms of pathogenesis, olfactory testing, anosmia as predictive tool, pathological examinations, imaging findings, affected factors, co-existing diseases, treatments, prognosis, hypothesis theories, and future directions.
RESULTS
The possible pathogenesis of COVID-19-induced anosmia may involve inflammation of the olfactory clefts and damage to the olfactory epithelium or olfactory central nervous system by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The D614G spike variant may also play a role in the increased number of anosmia patients. Anosmia may also be an essential indicator of COVID-19 spread and an early indicator of the effectiveness of political decisions. The occurrence and development of COVID-19-induced anosmia may be influenced by smoking behaviors and underlying diseases such as type 2 diabetes, gastroesophageal disorders, and rhinitis. Most patients with COVID-19-induced anosmia can fully or partially recover their olfactory function for varying durations. COVID-19-induced anosmia can be treated with various approaches such as glucocorticoids and olfactory training.
CONCLUSION
Anosmia is one of the main features of COVID-19 and the underlying disease of the patient may also influence its occurrence and development. The possible pathogenesis of COVID-19-induced anosmia is very complicated, which may involve inflammation of the olfactory clefts and damage to the olfactory epithelium or olfactory central nervous system.
Topics: COVID-19; Humans; Anosmia; SARS-CoV-2; Olfactory Mucosa; Olfaction Disorders
PubMed: 34587819
DOI: 10.1177/01455613211048998 -
Biomolecules Oct 2023COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19... (Review)
Review
COVID-19 patients can exhibit a wide range of clinical manifestations affecting various organs and systems. Neurological symptoms have been reported in COVID-19 patients, both during the acute phase of the illness and in cases of long-term COVID. Moderate symptoms include ageusia, anosmia, altered mental status, and cognitive impairment, and in more severe cases can manifest as ischemic cerebrovascular disease and encephalitis. In this narrative review, we delve into the reported neurological symptoms associated with COVID-19, as well as the underlying mechanisms contributing to them. These mechanisms include direct damage to neurons, inflammation, oxidative stress, and protein misfolding. We further investigate the potential of small molecules from natural products to offer neuroprotection in models of neurodegenerative diseases. Through our analysis, we discovered that flavonoids, alkaloids, terpenoids, and other natural compounds exhibit neuroprotective effects by modulating signaling pathways known to be impacted by COVID-19. Some of these compounds also directly target SARS-CoV-2 viral replication. Therefore, molecules of natural origin show promise as potential agents to prevent or mitigate nervous system damage in COVID-19 patients. Further research and the evaluation of different stages of the disease are warranted to explore their potential benefits.
Topics: Humans; COVID-19; Neuroprotective Agents; SARS-CoV-2; Nervous System Diseases; Encephalitis
PubMed: 38002267
DOI: 10.3390/biom13111585 -
The Lancet. Microbe Aug 2023The most prevalent symptoms of post-COVID-19 condition are pulmonary dysfunction, fatigue and muscle weakness, anxiety, anosmia, dysgeusia, headaches, difficulty in... (Review)
Review
The most prevalent symptoms of post-COVID-19 condition are pulmonary dysfunction, fatigue and muscle weakness, anxiety, anosmia, dysgeusia, headaches, difficulty in concentrating, sexual dysfunction, and digestive disturbances. Hence, neurological dysfunction and autonomic impairments predominate in post-COVID-19 condition. Tachykinins including the most studied substance P are neuropeptides expressed throughout the nervous and immune systems, and contribute to many physiopathological processes in the nervous, immune, gastrointestinal, respiratory, urogenital, and dermal systems and participate in inflammation, nociception, and cell proliferation. Substance P is a key molecule in neuroimmune crosstalk; immune cells near the peripheral nerve endings can send signals to the brain with cytokines, which highlights the important role of tachykinins in neuroimmune communication. We reviewed the evidence that relates the symptoms of post-COVID-19 condition to the functions of tachykinins and propose a putative pathogenic mechanism. The antagonism of tachykinins receptors can be a potential treatment target.
Topics: Humans; Substance P; COVID-19; Tachykinins; Neuropeptides; Receptors, Tachykinin
PubMed: 37327802
DOI: 10.1016/S2666-5247(23)00111-8 -
Frontiers in Neuroscience 2023COVID-19 induces both acute and chronic neurological changes. Existing evidence suggests that chemosensory changes, particularly olfactory loss, may reflect central... (Review)
Review
INTRODUCTION
COVID-19 induces both acute and chronic neurological changes. Existing evidence suggests that chemosensory changes, particularly olfactory loss, may reflect central neurological dysfunction in neurodegenerative diseases and mark progression from mild cognitive impairment to Alzheimer's. This scoping review summarizes the available literature to evaluate the relationship between neurocognition and olfaction in young to middle-aged adults with minimal comorbidities following COVID-19 infection.
METHODS
A literature search of PubMed, Ovid Embase, Web of Science, and Cochrane Library was conducted. Studies underwent title/abstract and full text screening by two reviewers, with a third reviewer resolving any conflicts. Remaining studies underwent data extraction.
RESULTS
Seventeen studies were eligible for data extraction after the review process, where 12 studies found significantly poorer cognition in those suffering from olfactory dysfunction, four studies showed no association between cognition and olfaction, and one study reported lower anosmia prevalence among patients with cognitive impairment.
CONCLUSION
The majority of studies in this review find that olfactory dysfunction is associated with poorer cognition. More rigorous studies are needed to further elucidate the relationship between olfaction and cognition after COVID-19.
PubMed: 37457004
DOI: 10.3389/fnins.2023.1198267 -
Biomedicines Aug 2023Research on the longer-term sequelae of COVID-19 in patients with asthma is limited. (Review)
Review
BACKGROUND
Research on the longer-term sequelae of COVID-19 in patients with asthma is limited.
OBJECTIVE
To assess the frequency and severity of long-term symptoms of COVID-19 in the population of asthma patients.
METHODS
A systematic review of the published literature was conducted in accordance with the recommendations of the PRISMA statement. EMBASE, MEDLINE/PubMed, Web of Science, CINAHL, and Scopus Scholar were searched for terms related to asthma and post or long COVID-19, and for systematic reviews related to specific questions within our review, up to June 2022.
RESULTS
Data from 9 references publications included in the review were extracted. A total of 1466 adult asthmatic patients with COVID-19 infection were described in all the publications mentioned above. Of the long-term symptoms reported after COVID-19, patients indicated: lower respiratory symptoms, fatigue, cognitive symptoms, psychological problems, and other such as skin rashes, gastrointestinal disorders, tachycardia, palpitations, ocular disorders, ageusia/hypogeusia, anosmia/hyposmia, and poor sleep quality. These symptoms in similar intensity were observed in the comparison groups without a diagnosis of asthma.
CONCLUSIONS
The published data neither confirm nor deny that long-term COVID-19 symptoms in patients with asthma diagnosis are different in strength and frequency from patients without asthma diagnosis. To indicate associations between asthma and COVID-19 infection and severity, as well as the frequency of long-term symptoms of COVID-19, more longitudinal research is needed in chronic asthma patients with different phenotypes, intensity of treatment, and degree of asthma control.
PubMed: 37626764
DOI: 10.3390/biomedicines11082268 -
Emerging Microbes & Infections Dec 2023Coronavirus disease 2019 (COVID-19) cases in China has grown rapidly after adjustment of the dynamic zero-COVID-19 strategy. However, how different vaccination states...
Coronavirus disease 2019 (COVID-19) cases in China has grown rapidly after adjustment of the dynamic zero-COVID-19 strategy. However, how different vaccination states affect symptoms, severity and post COVID conditions was unclear. Here, we used an online questionnaire to investigate the infection status of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among 11,897 participants, with 55.55% positive and 28.42% negative. The common COVID-19 symptoms were fatigue (73.31%), cough (70.02%), fever (65.25%) and overall soreness (58.64%); self-reported asymptomatic infection accounted for 0.7% of participants. The persistent symptoms at 1 month after infection included fatigue (48.7%), drowsiness (34.3%), cough (30.1%), decreased exercise ability (23.1%) and pharyngeal discomfort (19.4%), which was reduced by more than 200% at 2 months. Participants with complications such as chronic obstructive pulmonary disease, respiratory diseases, diabetes, hypertension, etc. have a higher proportion of hospitalization and longer recovery time (< = 0.01). Multiple vaccination statuses reduced the infection ( < 0.001) and severity rates ( = 0.022) by varying degrees as well as reduced the risk of high fever (>39.1 °C), chills, diarrhea and ageusia/anosmia, respectively ( < 0.05). Vaccination may enhance some upper respiratory symptoms, including sore throat, nasal congestion and runny nose, respectively ( < 0.05). Participants who had been vaccinated within 3 months were better protected by helping reduce their risk of overall soreness, chills and ageusia/anosmia, respectively ( < 0.05). In conclusion, our work has updated the epidemic characteristics of the breakthrough infection (BTI) wave after the dynamic zero-COVID-19 strategy, providing data and insights on how different vaccination statuses affect COVID-19 symptoms and disease prognosis.
Topics: Humans; COVID-19; SARS-CoV-2; Ageusia; Anosmia; Breakthrough Infections; Chills; Cough; China; Fatigue; Surveys and Questionnaires
PubMed: 37691586
DOI: 10.1080/22221751.2023.2258232 -
Vaccines Nov 2023The impact of long-COVID-19 syndrome is rather variable, since it is influenced by several residual confounders. This study aimed to investigate the prevalence of long...
A Multi-Center Study Investigating Long COVID-19 in Healthcare Workers from North-Eastern Italy: Prevalence, Risk Factors and the Impact of Pre-Existing Humoral Immunity-ORCHESTRA Project.
The impact of long-COVID-19 syndrome is rather variable, since it is influenced by several residual confounders. This study aimed to investigate the prevalence of long COVID-19 in healthcare workers (HCWs) from four university hospitals in north-eastern Italy: Trieste, Padua, Verona, and Modena-Reggio Emilia. During the period June 2022-August 2022, HCWs were surveyed for past COVID-19 infections, medical history, and any acute as well as post-COVID-19 symptoms. The prevalence of long COVID-19 was estimated at 30-60 days or 61+ days since first negative swab following first and second COVID-19 episode. Furthermore, the risk of long COVID-19 was investigated by multivariable logistic regression. Results were expressed as the adjusted odds ratio (aOR) with a 95% confidence interval (95%CI). 5432 HCWs returned a usable questionnaire: 2401 were infected with SARS-CoV-2 at least once, 230 were infected at least twice, and 8 were infected three times. The prevalence of long COVID-19 after a primary COVID-19 infection was 24.0% at 30-60 days versus 16.3% at 61+ days, and 10.5% against 5.5% after the second SARS-CoV-2 event. The most frequent symptoms after a first COVID-19 event were asthenia (30.3%), followed by myalgia (13.7%), cough (12.4%), dyspnea (10.2%), concentration deficit (8.1%), headache (7.3%), and anosmia (6.5%), in decreasing order of prevalence. The risk of long COVID-19 at 30-60 days was significantly higher in HCWs hospitalized for COVID-19 (aOR = 3.34; 95%CI: 1.62; 6.89), those infected with SARS-CoV-2 during the early pandemic waves-namely the Wuhan (aOR = 2.16; 95%CI: 1.14; 4.09) or Alpha (aOR= 2.05; 95%CI: 1.25; 3.38) transmission periods-and progressively increasing with viral shedding time (VST), especially 15+ days (aOR = 3.20; 95%CI: 2.07; 4.94). Further determinants of long COVID-19 at 30-60 days since primary COVID-19 event were female sex (aOR = 1.91; 95%CI: 1.30; 2.80), age >40 years, abnormal BMI, or administrative services (reference category). In contrast, HCWs vaccinated with two doses before their primary infection (aOR = 0.57; 95%CI: 0.34; 0.94), undergraduate students, or postgraduate medical trainees were less likely to experience long COVID-19 at 30-60 days. Apart from pandemic waves, the main determinants of long COVID-19 at 30-60 days were confirmed at 61+ days. The risk of long COVID-19 following primary infection increased with the severity of acute disease and VST, especially during the initial pandemic waves, when more virulent viral strains were circulating, and susceptibility to SARS-CoV-2 was higher since most HCWs had not been infected yet, COVID-19 vaccines were still not available, and/or vaccination coverage was still building up. The risk of long COVID-19 therefore decreased inversely with humoral immunity at the individual level. Nevertheless, the prevalence of long COVID-19 was remarkably lower after SARS-CoV-2 reinfections regardless of vaccination status, suggesting that hybrid humoral immunity did not increase protection against the syndrome compared to immunity mounted by either natural infection or vaccination separately. Since the risk of long COVID-19 is currently low with Omicron and patients who developed the syndrome following SARS-CoV-2 infection in the early pandemic waves tend to return to a state of full health with time, a cost-effective approach to screen post-COVID-19 symptoms during the Omicron time could be restricted to vulnerable individuals developing severe disease and/or with prolonged VST.
PubMed: 38140174
DOI: 10.3390/vaccines11121769