Olfactory and taste dysfunction among mild-to-moderate symptomatic COVID-19 positive health care workers: An international survey

Olfactory Dysfunction in Healthcare Workers with COVID-19: Prevalence and Associated Factors

BACKGROUND

The COVID-19 pandemic is a real global health crisis. Its clinical presentation has evolved over time with an increasing number of symptoms. Olfactory dysfunction (OD) has recently been recognized as a frequent symptom relevant to screening for COVID-19, especially in pauci-asymptomatic forms. However, the underlying mechanisms of OD are not yet fully understood.

AIM

To determine the prevalence of OD in healthcare workers with SARS-CoV-2 and to identify its associated factors.

METHODS

This is a cross-sectional, analytical study, carried out during a period of six months and including all healthcare workers at Farhat Hached Academic Hospital (Tunisia) who were diagnosed with SARS-CoV-2 by PCR, RAT, or chest CT scan.

RESULTS

A total of 474 healthcare workers were included, representing a participation rate of 85.4%. The mean age was 41.02±10.67 years with a sex ratio of 0.2. The distribution of this population by department noted that it was mainly maternity (13.9%). The most presented workstation was nursing (31.4%). OD represented 39.2% of the reasons for consultation. Hospitalization was indicated in 16 patients (3.4%). The average duration of hospitalization was 8.87 ± 7.8 days. The average time off work was 17.04 ± 11.6 days. OD persisted for more than 90 days in 35 patients (7.4%). After multiple binary logistic regression, OD was statistically associated with female gender (p =0.001; OR 95% CI: 2.46 [1.4-4.2]) and blue-collar occupational category (p =0.002; OR IC95%:3.1 [1.5-6.5]). A significant association was also noted between OD and professional seniority and absence from work duration (p =0.019; OR 95% CI: 0.97 [0.95-0.99] and p =0.03; OR 95% CI: 0.97 [0.95-0.99]) respectively.

CONCLUSION

OD is common in COVID-19 patients. The identification of its associated factors may contribute to enhancing the understanding of its mechanism and drive therapeutic options.

Clinical factors influencing olfactory performance in patients with persistent COVID-19 smell loss longer than 1 year

Objectives

Factors affecting persistence of COVID-19-related olfactory dysfunction (OD) remain partially unknown. We aim to evaluate the clinical factors which could influence olfactory performance in patients with persistent COVID-19-related smell loss.

Methods

A retrospective analysis of 100 patients with persistent COVID-19-related OD was performed between October 2020 and December 2022 at a single-center long-COVID smell clinic. All subjects underwent smell assessment using Sniffin' Sticks (S'S) extended test, nasal endoscopy, nasal airflow evaluation (peak nasal inspiratory flow [PNIF]), allergy test (skin prick test [SPT]) for common aeroallergens, MRI of the head and patient-reported outcome measures (PROMs-VAS, SF-36, Short QOD-NS, SNOT-22). Based on S'S score, subjects were divided into normosmics (TDI ≥ 30.75) and dysosmics (TDI < 30.75).

Results

The median age was 42 years and the median length of patient-reported OD was 1.4 years. 20 patients (20.0%) were normosmic at the time of S'S assessment. Dysosmic patients were found to have significantly lower scores at the SF-36 health domains for energy/fatigue (p = .0004) and emotional wellbeing (p = .04) when compared to normosmics. A moderate correlation (r = .45-.59) between S'S scores and some PROMs was also demonstrated. At the multivariate analysis higher PNIF scores positively influenced odor threshold (p = .001) while positivity to SPT negatively influenced odor identification (p = .04).

Conclusions

Impairment of nasal airflow and sensitivity to aeroallergens can negatively affect olfactory performance in COVID-19-related OD. Long-COVID smell loss deeply affects QoL although recovery of olfaction can bring it back to a normal range.

Level of Evidence

IV.

COVID-19 Oral Sequelae: Persistent Gustatory and Saliva Secretory Dysfunctions after Recovery from COVID-19

Diverse manifestations have been recognized to last for a long time in patients infected with SARS-CoV-2. However, understanding of oral sequelae after recovery from COVID-19 is relatively poor compared to that of oral symptoms in the acute phase of COVID-19 and other COVID-19 sequelae. The aim of the present study was to characterize persistent gustatory and saliva secretory dysfunctions and to speculate on their pathogenic mechanisms. Articles were retrieved by searching scientific databases with a cutoff date of September 30, 2022. The literature search indicated that ageusia/dysgeusia and xerostomia/dry mouth are reported by 1-45% of COVID-19 survivors at follow-ups of 21-365 days and by 2-40% of COVID-19 survivors at follow-ups of 28-230 days, respectively. The prevalence of gustatory sequelae partly depends on difference in ethnicity, gender, age, and disease severity of subjects. Co-occurring gustatory and saliva secretory sequelae are pathogenically related to either or both of the following: expression of SARS-CoV-2 cellular entry-relevant receptors in taste buds and salivary glands, and SARS-CoV-2 infection-induced deficiency in zinc that is essential for normality of taste perception and saliva secretion. Given the long-term oral sequelae, hospital discharge is not the end of the disease; therefore, careful attention should be continuously paid to oral conditions of post-COVID-19 patients.

Exercise tolerance, fatigue, mental health, and employment status at 5 and 12 months following COVID-19 illness in a physically trained population

Failure to recover following severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may have a profound impact on individuals who participate in high-intensity/volume exercise as part of their occupation/recreation. The aim of this study was to describe the longitudinal cardiopulmonary exercise function, fatigue, and mental health status of military-trained individuals (up to 12-mo postinfection) who feel recovered, and those with persistent symptoms from two acute disease severity groups (hospitalized and community-managed), compared with an age-, sex-, and job role-matched control. Eighty-eight participants underwent cardiopulmonary functional tests at baseline (5 mo following acute illness) and 12 mo; 25 hospitalized with persistent symptoms (hospitalized-symptomatic), 6 hospitalized and recovered (hospitalized-recovered); 28 community-managed with persistent symptoms (community-symptomatic); 12 community-managed, now recovered (community-recovered), and 17 controls. Cardiopulmonary exercise function and mental health status were comparable between the 5 and 12-mo follow-up. At 12 mo, symptoms of fatigue (48% and 46%) and shortness of breath (SoB; 52% and 43%) remain high in hospitalized-symptomatic and community-symptomatic groups, respectively. At 12 mo, COVID-19-exposed participants had a reduced capacity for work at anaerobic threshold and at peak exercise levels of deconditioning persist, with many individuals struggling to return to strenuous activity. The prevalence considered "fully fit" at 12 mo was lowest in symptomatic groups (hospitalized-symptomatic, 4%; hospitalized-recovered, 50%; community-symptomatic, 18%; community-recovered, 82%; control, 82%) and 49% of COVID-19-exposed participants remained medically nondeployable within the British Armed Forces. For hospitalized and symptomatic individuals, cardiopulmonary exercise profiles are consistent with impaired metabolic efficiency and deconditioning at 12 mo postacute illness. The long-term deployability status of COVID-19-exposed military personnel is uncertain.NEW & NOTEWORTHY Subjective exercise limiting symptoms such as fatigue and shortness of breath reduce but remain prevalent in symptomatic groups. At 12 mo, COVID-19-exposed individuals still have a reduced capacity for work at the anaerobic threshold (which best predicts sustainable intensity), despite oxygen uptake comparable to controls. The prevalence of COVID-19-exposed individuals considered "medically non-deployable" remains high at 47%.

Cardiopulmonary, Functional, Cognitive and Mental Health Outcomes Post-COVID-19, Across the Range of Severity of Acute Illness, in a Physically Active, Working-Age Population

BACKGROUND

The COVID-19 pandemic has led to significant morbidity and mortality, with the former impacting and limiting individuals requiring high physical fitness, including sportspeople and emergency services.

METHODS

Observational cohort study of 4 groups: hospitalised, community illness with on-going symptoms (community-symptomatic), community illness now recovered (community-recovered) and comparison. A total of 113 participants (aged 39 ± 9, 86% male) were recruited: hospitalised (n = 35), community-symptomatic (n = 34), community-recovered (n = 18) and comparison (n = 26), approximately five months following acute illness. Participant outcome measures included cardiopulmonary imaging, submaximal and maximal exercise testing, pulmonary function, cognitive assessment, blood tests and questionnaires on mental health and function.

RESULTS

Hospitalised and community-symptomatic groups were older (43 ± 9 and 37 ± 10, P = 0.003), with a higher body mass index (31 ± 4 and 29 ± 4, P < 0.001), and had worse mental health (anxiety, depression and post-traumatic stress), fatigue and quality of life scores. Hospitalised and community-symptomatic participants performed less well on sub-maximal and maximal exercise testing. Hospitalised individuals had impaired ventilatory efficiency (higher VE/V̇CO₂ slope, 29.6 ± 5.1, P < 0.001), achieved less work at anaerobic threshold (70 ± 15, P < 0.001) and peak (231 ± 35, P < 0.001), and had a reduced forced vital capacity (4.7 ± 0.9, P = 0.004). Clinically significant abnormal cardiopulmonary imaging findings were present in 6% of hospitalised participants. Community-recovered individuals had no significant differences in outcomes to the comparison group.

CONCLUSION

Symptomatically recovered individuals who suffered mild-moderate acute COVID-19 do not differ from an age-, sex- and job-role-matched comparison population five months post-illness. Individuals who were hospitalised or continue to suffer symptoms may require a specific comprehensive assessment prior to return to full physical activity.

Long-Term COVID-19 Smell and Taste Disorders Differ Significantly from Other Post-Infectious Cases

INTRODUCTION

COVID-19 is causing a wide range of clinical manifestations. Severe complications and long-lasting sequelae have been identified. Thus, olfactory disorders are reported in up to 86% of cases in mild and moderate COVID-19 infections. We present the first study comparing simple and complex post-COVID-19 cases with matched non-COVID-19 post-infectious smell and taste disorders.

METHODS

A total of 328 patients were recruited from the University Clinic for Flavour, Balance and Sleep, Ear-nose-throat Department, Goedstrup Hospital, Denmark. A non-COVID -19 post-infectious population of 148 individuals was identified from the Redcap database, and was matched by duration of smell and taste disorders. Post-COVID-19 patients were divided into 99 patients with simple smell and taste disorders (only suffering from smell and taste disorders after COVID-19); and (81 patients with complex smell and taste disorder plus several other post-COVID-19 complaints). Besides patient-reported outcome measures (PROM) questionnaires and quality of life score (QoL), ear-nose-throat examination, Mini-Mental State Examination (MMSE), orthonasal smell test (Sniffing's sticks), retronasal quick test, and taste screening were performed.

RESULTS

Cases with post-COVID-19-related smell and taste disorders deviated from non-COVID-19 post-infectious cases; the patients were younger, had a lower occurrence of anosmia/ageusia, and had higher overall smell test scores. In contrast, patients with post-COVID-19-related smell and taste disorders more frequently complained of distorted senses. Parosmia and phantosmia were more prevalent among patients with simple post-COVID-19 complaints than among complex cases and their QoL were more negatively affected.

CONCLUSION

Smell and taste function differ significantly between post-COVID-19 and other non-COVID-19 post-viral cases.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:169-174, 2023.

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

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

Olfactory Training Impacts Olfactory Dysfunction Induced by COVID-19: A Pilot Study

INTRODUCTION

Olfactory dysfunction is one of the main symptoms of COVID-19 and may last beyond resolution of the infection. The most promising intervention for post-viral olfactory dysfunction is olfactory training (OT), which involves exposing the olfactory system to a range of odors daily. This approach is thought of promoting the regeneration of olfactory receptor cells, but its effectiveness in patients with post-COVID-19 olfactory dysfunction has yet to be confirmed.

METHODS

This double-blind randomized pilot study compared the effectiveness of OT versus placebo in the treatment of post-COVID-19 olfactory dysfunction. Twenty-five participants were recruited in each group. OT protocol consisted of sniffing 4 scents (rose, orange, clove, and eucalyptus) for 5 min twice daily for 12 weeks. Olfactory function was assessed before and after the training using (1) a validated odor identification test (UPSIT-40) and (2) a 10-point visual analog scale; we further assessed the presence of (3) parosmia.

RESULTS

While we did not observe any effect of OT on olfactory test scores, we observed a significant improvement of subjective olfactory function in the intervention group, while no such effect was observed in the placebo group. Finally, the frequency of parosmia was significantly lower in the intervention group.

CONCLUSIONS

This study highlights an increase in subjective but not objective olfactory function when performing OT for 12 weeks. Further, parosmia seems to be positively affected by OT. These results may serve as a starting point for larger scale studies to assess the efficacy of OT for treatment of post-COVID-19 olfactory dysfunction.

A multicenter real-life study to determine the efficacy of corticosteroids and olfactory training in improving persistent COVID-19-related olfactory dysfunction

Background

No definitive treatment exists to effectively restore function in patients with persistent post-infectious olfactory dysfunction (OD). Corticosteroids have been considered as a therapeutic option in post-infectious OD but their benefit in COVID-19-related OD remains unexplored. We aim to determine the role of the combination of corticosteroids plus olfactory training (OT) in improving persistent COVID-19-related OD.

Methods

A multicenter real-life cohort study was conducted between December 2020 and April 2022 on patients with reported COVID-19-related OD. Only patients with confirmed OD at Sniffin' Sticks (S'S) and those who attended their 6-month follow-up were included. Patients were started on a combined treatment of corticosteroids and OT. Patients refusing corticosteroids or not doing any treatment formed the control groups. Visual analogue scale (VAS) for sense of smell and SNOT-22 were used to assess patients reported symptoms.

Results

Sixty-seven subjects with reported COVID-19-related OD were initially seen. Normosmic patients at S'S (n = 14) and those not attending their follow-up (n = 9) were excluded. Of the 44 patients included in the analysis, 19 patients had the combined treatment (group A), 16 patients refused to take corticosteroids and did the OT alone (group B) whereas 9 patients did not do any treatment (group C). An improvement of threshold + discrimination + identification (TDI) score (p = .01) and VAS for smell (p = .01) was found in group A whereas only the TDI score improved in group B (p = .04). Presence of comorbidities, age, sex (male), and length of OD negatively influenced olfactory recovery.

Conclusions

Our study confirms the importance of OT in long-term OD suggesting that the addition of corticosteroids may give a benefit in terms of patient's perceived olfaction.

Level of Evidence

2b.

A survey of changes in taste and food preferences related to the coronavirus disease (COVID-19) in Hungary

A plethora of research and empiric observation supported the claim that–among other symptoms–diseases often affect the ability to smell and the sense of taste, possibly affecting the taste- and food preferences as well.

The aim of the present study was to shed light on the impact of COVID-related smell- (dysosmia/anosmia) and taste function-disorder/loss (dysgeusia/ageusia) on the food and taste preferences COVID-19 patients of different symptomatic and pre-existing conditions and demographic backgrounds.

The research based on a descriptive, cross-sectional survey. In total, 514 participants filled our self-administered online questionnaire. Thirteen participants were excluded according to the exclusion criteria. Descriptive statistics, Chi-square test, t-test for correlation coefficient, were performed.

The most common long COVID symptom was fatigue/weakness (53.1%) followed by anosmia (50.9%) and tachycardia (33.5%). Many participants reported dysgeusia/ageusia during the acute phase of the disease, which sometimes prevailed as a long COVID symptom. A high percentage of participants reported that they rejected all kinds of meat of animal origin except cold cuts for their duration of recuperation, which proved to be the most common dietary change during the post-COVID period so far.

Prognosis and persistence of smell and taste dysfunction in patients with covid-19: meta-analysis with parametric cure modelling of recovery curves

OBJECTIVE

To clarify in patients with covid-19 the recovery rate of smell and taste, proportion with persistent dysfunction of smell and taste, and prognostic factors associated with recovery of smell and taste.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase, Scopus, Cochrane Library, and medRxiv from inception to 3 October 2021.

REVIEW METHODS

Two blinded reviewers selected observational studies of adults (≥18 years) with covid-19 related dysfunction of smell or taste. Descriptive prognosis studies with time-to-event curves and prognostic association studies of any prognostic factor were included.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted data, evaluated study bias using QUIPS, and appraised evidence quality using GRADE, following PRISMA and MOOSE reporting guidelines. Using iterative numerical algorithms, time-to-event individual patient data (IPD) were reconstructed and pooled to retrieve distribution-free summary survival curves, with recovery rates reported at 30 day intervals for participants who remained alive. To estimate the proportion with persistent smell and taste dysfunction, cure fractions from Weibull non-mixture cure models of plateaued survival curves were logit transformed and pooled in a two stage meta-analysis. Conventional aggregate data meta-analysis was performed to explore unadjusted associations of prognostic factors with recovery.

MAIN OUTCOME MEASURES

The primary outcomes were the proportions of patients remaining with smell or taste dysfunction. Secondary outcomes were the odds ratios of prognostic variables associated with recovery of smell and taste.

RESULTS

18 studies (3699 patients) from 4180 records were included in reconstructed IPD meta-analyses. Risk of bias was low to moderate; conclusions remained unaltered after exclusion of four high risk studies. Evidence quality was moderate to high. Based on parametric cure modelling, persistent self-reported smell and taste dysfunction could develop in an estimated 5.6% (95% confidence interval 2.7% to 11.0%, I2=70%, τ2=0.756, 95% prediction interval 0.7% to 33.5%) and 4.4% (1.2% to 14.6%, I2=67%, τ2=0.684, 95% prediction interval 0.0% to 49.0%) of patients, respectively. Sensitivity analyses suggest these could be underestimates. At 30, 60, 90, and 180 days, respectively, 74.1% (95% confidence interval 64.0% to 81.3%), 85.8% (77.6% to 90.9%), 90.0% (83.3% to 94.0%), and 95.7% (89.5% to 98.3%) of patients recovered their sense of smell (I2=0.0-77.2%, τ2=0.006-0.050) and 78.8% (70.5% to 84.7%), 87.7% (82.0% to 91.6%), 90.3% (83.5% to 94.3%), and 98.0% (92.2% to 95.5%) recovered their sense of taste (range of I2=0.0-72.1%, τ2=0.000-0.015). Women were less likely to recover their sense of smell (odds ratio 0.52, 95% confidence interval 0.37 to 0.72, seven studies, I2=20%, τ2=0.0224) and taste (0.31, 0.13 to 0.72, seven studies, I2=78%, τ2=0.5121) than men, and patients with greater initial severity of dysfunction (0.48, 0.31 to 0.73, five studies, I2=10%, τ2<0.001) or nasal congestion (0.42, 0.18 to 0.97, three studies, I2=0%, τ2<0.001) were less likely to recover their sense of smell.

CONCLUSIONS

A substantial proportion of patients with covid-19 might develop long lasting change in their sense of smell or taste. This could contribute to the growing burden of long covid.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021283922.

Clinical and occupational risk factors for coronavirus disease 2019 (COVID-19) in healthcare personnel

Objective

To identify characteristics associated with positive severe acute respiratory coronavirus virus 2 (SARS-CoV-2) polymerase chain reaction (PCR) tests in healthcare personnel.

Design

Retrospective cohort study.

Setting

A multihospital healthcare system.

Participants

Employees who reported SARS-CoV-2 exposures and/or symptoms of coronavirus disease 2019 (COVID-19) between March 30, 2020, and September 20, 2020, and were subsequently referred for SARS-CoV-2 PCR testing.

Methods

Data from exposure and/or symptom reports were linked to the corresponding SARS-CoV-2 PCR test result. Employee demographic characteristics, occupational characteristics, SARS-CoV-2 exposure history, and symptoms were evaluated as potential risk factors for having a positive SARS-CoV-2 PCR test.

Results

Among 6,289 employees who received SARS-CoV-2 PCR testing, 873 (14%) had a positive test. Independent risk factors for a positive PCR included: working in a patient care area (relative risk [RR], 1.82; 95% confidence interval [CI], 1.37-2.40), having a known SARS-CoV-2 exposure (RR, 1.20; 95% CI, 1.04-1.37), reporting a community versus an occupational exposure (RR, 1.87; 95% CI, 1.49-2.34), and having an infected household contact (RR, 2.47; 95% CI, 2.11-2.89). Nearly all HCP (99%) reported symptoms. Symptoms associated with a positive PCR in a multivariable analysis included loss of sense of smell (RR, 2.60; 95% CI, 2.09-3.24) or taste (RR, 1.75; 95% CI, 1.40-2.20), cough (RR, 1.95; 95% CI, 1.40-2.20), fever, and muscle aches.

Conclusions

In this cohort of >6,000 healthcare system and academic medical center employees early in the pandemic, community exposures, and particularly household exposures, were associated with greater risk of SARS-CoV-2 infection than occupational exposures. This work highlights the importance of COVID-19 prevention in the community and in healthcare settings to prevent COVID-19.

COVID-19 Induced Taste Dysfunction and Recovery: Association with Smell Dysfunction and Oral Health Behaviour

Background and Objectives: Disruption to taste and smell are common symptoms of COVID-19 infection. The current literature overlooks taste symptoms and tends to focus on the sense of smell. Persisting cases (>28 days) of taste dysfunction are increasingly recognised as a major future healthcare challenge. This study focuses on the severity and recovery of COVID-19 induced taste loss and association with olfactory symptoms, lifestyle and oral health factors. Materials and Methods: This study was a cross-sectional survey comparing 182 rapid taste recovery participants (≤28 days) with 47 participants with prolonged taste recovery >28 days. Analyses of taste loss in association with smell loss, age, sex, illness severity, diet, BMI, vitamin-D supplementation, antidepressants, alcohol use, smoking, brushing frequency, flossing, missing teeth, appliances and number of dental restorations were conducted. Differences in the severity of the loss of sour, sweet, salt, bitter and umami tastes were explored. Results: Both the severity and the duration of taste and smell loss were closely correlated (p < 0.001). Salt taste was significantly less affected than all other taste qualities (p < 0.001). Persisting taste loss was associated with older age (mean ± 95% CI = 31.73 ± 1.23 years vs. 36.66 ± 3.59 years, p < 0.001) and reduced likelihood of using floss (odds ratio ± 95% CI = 2.22 (1.15−4.25), p = 0.047). Conclusions: Smell and taste loss in COVID-19 are closely related, although a minority of individuals can experience taste or smell dysfunction in the absence of the other. The taste of salt may be less severely affected than other taste qualities and future work exploring this finding objectively is indicated. The association of flossing with rapid taste recovery adds to the growing evidence of a link between good periodontal health and favourable COVID-19 outcomes.

Long-Lasting Olfactory Dysfunction in Hospital Workers Due to COVID-19: Prevalence, Clinical Characteristics, and Most Affected Odorants

Hospital workers have increased exposure risk of healthcare-associated infections due to the frontline nature of their work. Olfactory dysfunction is highly prevalent. The objectives for this investigation are to study the prevalence of long-lasting olfactory dysfunction associated with COVID-19 infection in hospital workers during the first pandemic wave, to identify clinical characteristics and associated symptomatology, and to analyze how many patients with COVID-19 infection had developed olfactory dysfunction during infection and maintained a reduced olfactory function for approximately 10 weeks after diagnosis. Between June and July of 2020, a cross-sectional study was carried out at the Hospital Central de la Cruz Roja San José and Santa Adela in Madrid, Spain. One hundred sixty-four participants were included, of which 110 were patient-facing healthcare staff and 54 were non-patient-facing healthcare staff. Participants were split into three groups, according to COVID-19 diagnosis and presence of COVID-19 related olfactory symptomatology. Participants were asked to complete a structured online questionnaire along with Sniffin' Stick Olfactory Test measurements. In this study, 88 participants were confirmed for COVID-19 infection, 59 of those participants also reported olfactory symptomatology. The prevalence of COVID-19 infection was 11.35%, and the prevalence for olfactory dysfunction was 67.05%. Olfactory dysfunction associated with COVID-19 infection leads to long-lasting olfactory loss. Objective assessment with Sniffin' Stick Olfactory Test points to odor identification as the most affected process. Lemon, liquorice, solvent, and rose are the odors that are worst recognized. Mint, banana, solvent, garlic, coffee, and pineapple, although they are identified, are perceived with less intensity. The findings of this study confirmed a high prevalence of SARS-CoV-2 infection among the hospital workers.

Long‐term prevalence of taste and olfactory dysfunction in COVID‐19 patients: A cross‐sectional study

Objectives

The objectives of the study were to investigate the long‐term prevalence of taste disorder (TD) and olfactory disorder (OD) and associated risk factors in the non‐hospitalized southeastern Brazil population of COVID‐19 patients.

Methods

This cross‐sectional open survey evaluated possible long‐term OD and TD in non‐hospitalized patients who had been diagnosed with COVID‐19 for more than 30 days, through an online self‐report questionnaire. Demographic data, comorbidities, symptoms, and the intensity of OD and TD at the time of diagnosis and at the time of completing the questionnaire were evaluated.

Results

Three hundred five responses were included. The reported prevalence of OD and TD was 72.9% and 67.4%, respectively, in the moment of diagnosis; after a mean follow‐up period of 179 days, 45% and 50% still had some degree of the symptoms. There was a positive correlation between age and the high prevalence of OD (p = 0.02). However, there was no correlation between age and TD (p = 0.961) and weight in relation to OD/TD (p = 0.500 and p = 0.636, respectively).

Conclusion

This study observed a high long‐term prevalence of OD and TD associated with COVID‐19, with a low recovery rate during the study period. There was a positive association between older participants and the prevalence of OD.

Gustatory and Saliva Secretory Dysfunctions in COVID-19 Patients with Zinc Deficiency

Given the ever-progressing studies on coronavirus disease 2019 (COVID-19), it is critical to update our knowledge about COVID-19 symptomatology and pathophysiology. In the present narrative review, oral symptoms were overviewed using the latest data and their pathogenesis was hypothetically speculated. PubMed, LitCovid, ProQuest, and Google Scholar were searched for relevant studies from 1 April 2021 with a cutoff date of 31 January 2022. The literature search indicated that gustatory dysfunction and saliva secretory dysfunction are prevalent in COVID-19 patients and both dysfunctions persist after recovery from the disease, suggesting the pathogenic mechanism common to these cooccurring symptoms. COVID-19 patients are characterized by hypozincemia, in which zinc is possibly redistributed from blood to the liver at the expense of zinc in other tissues. If COVID-19 induces intracellular zinc deficiency, the activity of zinc-metalloenzyme carbonic anhydrase localized in taste buds and salivary glands may be influenced to adversely affect gustatory and saliva secretory functions. Zinc-binding metallothioneins and zinc transporters, which cooperatively control cellular zinc homeostasis, are expressed in oral tissues participating in taste and saliva secretion. Their expression dysregulation associated with COVID-19-induced zinc deficiency may have some effect on oral functions. Zinc supplementation is expected to improve oral symptoms in COVID-19 patients.

The Role of Social Media in Improving Patient Recruitment for Research Studies on Persistent Post-Infectious Olfactory Dysfunction

Background and Objectives: Since the COVID-19 pandemic, the number of cases of post-infectious olfactory dysfunction (PIOD) has substantially increased. Despite a good recovery rate, olfactory dysfunction (OD) becomes persistent in up to 15% of cases and further research is needed to find new treatment modalities for those patients who have not improved on currently available treatments. Social media has emerged as a potential avenue for patient recruitment, but its role in recruiting patients with smell dysfunction remains unexplored. We conducted a survey using the AbScent Facebook page to evaluate the feasibility of using this platform for future studies on smell dysfunction. Materials and Methods: Between 26 October and 4 November 2021, we conducted an online survey to evaluate propensity of patients with PIOD who would be willing to participate in research studies on smell dysfunction. Results: Sixty-five subjects were surveyed with a response rate of 90.7%. The median visual analogue scale (VAS) for sense of smell was 0 at infection and 2 at survey completion. The median length of OD was 1.6 years, and the main cause of OD was SARS-CoV-2 (57.6%). Parosmia was reported in 41 subjects (69.5%) whilst phantosmia in 22 (37.3%). The median length of olfactory training (OT) was 6 months but subjectively effective in 15 subjects (25.4%). Twenty-seven subjects (45.8%) tried other medications to improve olfaction, but only 6 participants (22.2%) reported an improvement. All subjects expressed their propensity to participate in future studies with most of them (38; 64.4%) willing to be enrolled either in medical and surgical studies or to be part of a randomised study design (11; 18.6%). Conclusions: Using the AbScent Facebook platform we successfully selected a population of subjects with persistent and severe OD that have failed to improve on available treatments and are willing to participate in further clinical trials.

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

OBJECTIVES

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

DESIGN

A single-centre cohort study.

SETTING

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

PARTICIPANTS

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSIONS

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

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

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

Iranian Smell Diagnostic Test in Covid-19 Disease; Report of Covid-19 Center of North of Iran

Background

SARS-CoV-2 is a pandemic coronavirus that causes the COVID-19 syndrome. In the pandemic of COVID-19 many patients were affected to new onset olfactory dysfunction. Since there is a dearth of research studies regarding the standard smell test, the present study was conducted to fill this gap.

Methods

The present retrospective cohort study was conducted on 250 clients with or without diagnosis of Covid-19 disease who referred to Covid-19 centers of North of Iran. Two groups were matched for age and sex. Data were collected by examination, demographic and clinical information questionnaire and Iranian smell diagnostic test. The binary logistic regression to estimate the odds ratio value in SPSS version 23.0 was used.

Results

One-hundred cases (42.2%) had hyposmia and 20 cases (8.4%) were found to have anosmia. Type of covid-19 sign and symptom were statistically significant with olfactory dysfunction (41 cases, 31.8%), fever (28 cases, 21.7%), weakness and dyspnea (15 cases, 11.6%), (p=0.0001). The urban residency equal OR=6.42 (3.04-13.53) to rural residency for olfactory dysfunction (p=0.0001). Covid-19 patients' OR=61.25 (27.36-137.11) chance to be affected by the olfactory dysfunction in compare to control group (p=0.0001). Also, with increasing age, chance of olfactory dysfunction changed from OR=0.61(1.16-0.13) to OR=1.89 (0.82-4.33). Furthermore, female chance OR=1.21 (0.72-2.03) and employee patients was OR=2.29 (1.30-4.04) to olfactory dysfunction.

Conclusion

Alf of the patients were affected by olfactory dysfunction. Furthermore, Covid-19 patients, urban residency, lower age, female and employee were the prognostic factors for olfactory dysfunction. The standard olfactory tests such as IR-SIT is suggested for screening and detecting the clients probably affected by covid-19 especially in younger ages.

Post COVID-19 Syndrome in Patients with Asymptomatic/Mild Form

Post COVID-19 Syndrome (PCS) is a complex of various symptoms developing a month or more after the acute phase of the disease. The cases of PCS development among patients with asymptomatic/mild forms are frequently reported; however, the pathogenesis of PCS in this group of patients is still not completely clear. The publications about COVID-19 which were published in online databases from December 2019 to September 2021 are analyzed in this review. According to the analysis, PCS develops on average in 30-60% of patients, mainly among women. Fatigue, shortness of breath, cough, and anosmia were reported as the most common symptoms. The possible association between the described PCS symptoms and brain damage was revealed. We assume the possibility of an alternative course of COVID-19, which develops in genetically predisposed individuals with a stronger immune response, in which it predominantly affects the cells of the nervous system, possibly with the presence of an autoimmune component, which might have similarity with chronic fatigue syndrome or autoimmune disautonomia. Thus, the gender (female) and the presence of anosmia during an asymptomatic or mild course of the disease can be predictive factors for the development of PCS, which can be caused by autoimmune damage to neurons, glia, and cerebral vessels.

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

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

More than 50 long-term effects of COVID-19: a systematic review and meta-analysis

COVID-19 can involve persistence, sequelae, and other medical complications that last weeks to months after initial recovery. This systematic review and meta-analysis aims to identify studies assessing the long-term effects of COVID-19. LitCOVID and Embase were searched to identify articles with original data published before the 1st of January 2021, with a minimum of 100 patients. For effects reported in two or more studies, meta-analyses using a random-effects model were performed using the MetaXL software to estimate the pooled prevalence with 95% CI. PRISMA guidelines were followed. A total of 18,251 publications were identified, of which 15 met the inclusion criteria. The prevalence of 55 long-term effects was estimated, 21 meta-analyses were performed, and 47,910 patients were included (age 17–87 years). The included studies defined long-COVID as ranging from 14 to 110 days post-viral infection. It was estimated that 80% of the infected patients with SARS-CoV-2 developed one or more long-term symptoms. The five most common symptoms were fatigue (58%), headache (44%), attention disorder (27%), hair loss (25%), and dyspnea (24%). Multi-disciplinary teams are crucial to developing preventive measures, rehabilitation techniques, and clinical management strategies with whole-patient perspectives designed to address long COVID-19 care.

Post-viral effects of COVID-19 in the olfactory system and their implications

BACKGROUND

The mechanisms by which any upper respiratory virus, including SARS-CoV-2, impairs chemosensory function are not known. COVID-19 is frequently associated with olfactory dysfunction after viral infection, which provides a research opportunity to evaluate the natural course of this neurological finding. Clinical trials and prospective and histological studies of new-onset post-viral olfactory dysfunction have been limited by small sample sizes and a paucity of advanced neuroimaging data and neuropathological samples. Although data from neuropathological specimens are now available, neuroimaging of the olfactory system during the acute phase of infection is still rare due to infection control concerns and critical illness and represents a substantial gap in knowledge.

RECENT DEVELOPMENTS

The active replication of SARS-CoV-2 within the brain parenchyma (ie, in neurons and glia) has not been proven. Nevertheless, post-viral olfactory dysfunction can be viewed as a focal neurological deficit in patients with COVID-19. Evidence is also sparse for a direct causal relation between SARS-CoV-2 infection and abnormal brain findings at autopsy, and for trans-synaptic spread of the virus from the olfactory epithelium to the olfactory bulb. Taken together, clinical, radiological, histological, ultrastructural, and molecular data implicate inflammation, with or without infection, in either the olfactory epithelium, the olfactory bulb, or both. This inflammation leads to persistent olfactory deficits in a subset of people who have recovered from COVID-19. Neuroimaging has revealed localised inflammation in intracranial olfactory structures. To date, histopathological, ultrastructural, and molecular evidence does not suggest that SARS-CoV-2 is an obligate neuropathogen. WHERE NEXT?: The prevalence of CNS and olfactory bulb pathosis in patients with COVID-19 is not known. We postulate that, in people who have recovered from COVID-19, a chronic, recrudescent, or permanent olfactory deficit could be prognostic for an increased likelihood of neurological sequelae or neurodegenerative disorders in the long term. An inflammatory stimulus from the nasal olfactory epithelium to the olfactory bulbs and connected brain regions might accelerate pathological processes and symptomatic progression of neurodegenerative disease. Persistent olfactory impairment with or without perceptual distortions (ie, parosmias or phantosmias) after SARS-CoV-2 infection could, therefore, serve as a marker to identify people with an increased long-term risk of neurological disease.

Comparison of Brain Activation Patterns during Olfactory Stimuli between Recovered COVID-19 Patients and Healthy Controls: A Functional Near-Infrared Spectroscopy (fNIRS) Study

Impaired sense of smell occurs in a fraction of patients with COVID-19 infection, but its effect on cerebral activity is unknown. Thus, this case report investigated the effect of COVID-19 infection on frontotemporal cortex activity during olfactory stimuli. In this preliminary study, patients who recovered from COVID-19 infection (n = 6) and healthy controls who never contracted COVID-19 (n = 6) were recruited. Relative changes in frontotemporal cortex oxy-hemoglobin during olfactory stimuli was acquired using functional near-infrared spectroscopy (fNIRS). The area under curve (AUC) of oxy-hemoglobin for the time interval 5 s before and 15 s after olfactory stimuli was derived. In addition, olfactory function was assessed using the Sniffin’ Sticks 12-identification test (SIT-12). Patients had lower SIT-12 scores than healthy controls (p = 0.026), but there were no differences in oxy-hemoglobin AUC between healthy controls and patients (p > 0.05). This suggests that past COVID-19 infection may not affect frontotemporal cortex function, and these preliminary results need to be verified in larger samples.

Characteristics of taste dysfunction in COVID-19 subjects coming from two different countries

Taste dysfunction (TD) has been recognised, together with olfactory dysfunction, as a key presenting symptom of COVID-19. The capability to recognise flavours, flavour intensities and aroma characteristics can be highly variable within the same population, as well as potentially diverse between culturally different populations. The aims of this study are to evaluate whether a difference in the types of TD presentation amongst COVID-19 positive subjects can be demonstrated and whether a difference exists between populations of different cultures.

More Than 50 Long-Term Effects of COVID-19: A Systematic Review and Meta-Analysis

Background. COVID-19, caused by SARS-CoV-2, can involve sequelae and other medical complications that last weeks to months after initial recovery, which has come to be called Long-COVID or COVID long-haulers. This systematic review and meta-analysis aims to identify studies assessing long-term effects of COVID-19 and estimates the prevalence of each symptom, sign, or laboratory parameter of patients at a post-COVID-19 stage. Methods . LitCOVID (PubMed and Medline) and Embase were searched by two independent researchers. All articles with original data for detecting long-term COVID-19 published before 1 st of January 2021 and with a minimum of 100 patients were included. For effects reported in two or more studies, meta-analyses using a random-effects model were performed using the MetaXL software to estimate the pooled prevalence with 95% CI. Heterogeneity was assessed using I 2 statistics. This systematic review followed Preferred Reporting Items for Systematic Reviewers and Meta-analysis (PRISMA) guidelines, although the study protocol was not registered. Results. A total of 18,251 publications were identified, of which 15 met the inclusion criteria. The prevalence of 55 long-term effects was estimated, 21 meta-analyses were performed, and 47,910 patients were included. The follow-up time ranged from 14 to 110 days post-viral infection. The age of the study participants ranged between 17 and 87 years. It was estimated that 80% (95% CI 65-92) of the patients that were infected with SARS-CoV-2 developed one or more long-term symptoms. The five most common symptoms were fatigue (58%), headache (44%), attention disorder (27%), hair loss (25%), and dyspnea (24%). All meta-analyses showed medium (n=2) to high heterogeneity (n=13). Conclusions . In order to have a better understanding, future studies need to stratify by sex, age, previous comorbidities, the severity of COVID-19 (ranging from asymptomatic to severe), and duration of each symptom. From the clinical perspective, multi-disciplinary teams are crucial to developing preventive measures, rehabilitation techniques, and clinical management strategies with whole-patient perspectives designed to address long COVID-19 care.

More than 50 Long-term effects of COVID-19: a systematic review and meta-analysis

COVID-19, caused by SARS-CoV-2, can involve sequelae and other medical complications that last weeks to months after initial recovery, which has come to be called Long-COVID or COVID long-haulers. This systematic review and meta-analysis aims to identify studies assessing long-term effects of COVID-19 and estimates the prevalence of each symptom, sign, or laboratory parameter of patients at a post-COVID-19 stage. LitCOVID (PubMed and Medline) and Embase were searched by two independent researchers. All articles with original data for detecting long-term COVID-19 published before 1st of January 2021 and with a minimum of 100 patients were included. For effects reported in two or more studies, meta-analyses using a random-effects model were performed using the MetaXL software to estimate the pooled prevalence with 95% CI. Heterogeneity was assessed using I2 statistics. This systematic review followed Preferred Reporting Items for Systematic Reviewers and Meta-analysis (PRISMA) guidelines, although the study protocol was not registered. A total of 18,251 publications were identified, of which 15 met the inclusion criteria. The prevalence of 55 long-term effects was estimated, 21 meta-analyses were performed, and 47,910 patients were included. The follow-up time ranged from 14 to 110 days post-viral infection. The age of the study participants ranged between 17 and 87 years. It was estimated that 80% (95% CI 65-92) of the patients that were infected with SARS-CoV-2 developed one or more long-term symptoms. The five most common symptoms were fatigue (58%), headache (44%), attention disorder (27%), hair loss (25%), and dyspnea (24%). All meta-analyses showed medium (n=2) to high heterogeneity (n=13). In order to have a better understanding, future studies need to stratify by sex, age, previous comorbidities, severity of COVID-19 (ranging from asymptomatic to severe), and duration of each symptom. From the clinical perspective, multi-disciplinary teams are crucial to developing preventive measures, rehabilitation techniques, and clinical management strategies with whole-patient perspectives designed to address long COVID-19 care.

Chemosensory Dysfunctions Induced by COVID-19 Can Persist up to 7 Months: A Study of Over 700 Healthcare Workers

Several studies have revealed either self-reported chemosensory alterations in large groups or objective quantified chemosensory impairments in smaller populations of patients diagnosed with COVID-19. However, due to the great variability in published results regarding COVID-19-induced chemosensory impairments and their follow-up, prognosis for chemosensory functions in patients with such complaints remains unclear. Our objective is to describe the various chemosensory alterations associated with COVID-19 and their prevalence and evolution after infection. A cross-sectional study of 704 healthcare workers with a RT–PCR-confirmed SARS-CoV-2 infection between 2020 February 28 and 2020 June 14 was conducted 3–7 months after onset of symptoms. Data were collected with an online questionnaire. Outcomes included differences in reported chemosensory self-assessment of olfactory, gustatory, and trigeminal functions across time points and Chemosensory Perception Test scores from an easy-to-use at-home self-administered chemosensory test. Among the 704 participants, 593 (84.2%) were women, the mean (SD) age was 42 (12) years, and the questionnaire was answered on average 4.8 (0.8) months after COVID-19. During COVID-19, a decrease in olfactory, gustatory, and trigeminal sensitivities was reported by 81.3%, 81.5%, and 48.0%, respectively. Three to 7 months later, reduced sensitivity was still reported by 52.0%, 41.9%, and 23.3%, respectively. Chemosensory Perception Test scores indicate that 19.5% of participants had objective olfactory impairment. These data suggest a significant proportion of COVID-19 cases have persistent chemosensory impairments at 3–7 months after their infection, but the majority of those who had completely lost their olfactory, gustatory, and trigeminal sensitivities have improved.