Olfactory and taste dysfunction in coronavirus disease 2019 patients: its prevalence and outcomes

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.

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.

Sudden loss of smell and taste: clinical predictors of coronavirus disease 2019 infection

Objectives

This study aimed: to evaluate the association between coronavirus disease 2019 infection and olfactory and taste dysfunction in patients presenting to the out-patient department with influenza-like illness, who underwent reverse transcription polymerase chain reaction testing for coronavirus; and to determine the sensitivity, specificity, and positive and negative predictive values of olfactory and taste dysfunction and other symptoms in these patients.

Methods

Patients presenting with influenza-like illness to the study centre in September 2020 were included in the study. The symptoms of patients who tested positive for coronavirus on reverse transcription polymerase chain reaction testing were compared to those with negative test results.

Results

During the study period, 909 patients, aged 12–70 years, presented with influenza-like illness; of these, 316 (34.8 per cent) tested positive for coronavirus. Only the symptoms of olfactory and taste dysfunction were statistically more significant in patients testing positive for coronavirus than those testing negative.

Conclusion

During the pandemic, patients presenting to the out-patient department with sudden loss of sense of smell or taste may be considered as positive for coronavirus disease 2019, until proven otherwise.

The Prevalence and Pathophysiology of Chemical Sense Disorder Caused by the Novel Coronavirus

Emerging viral infections are a ceaseless challenge and remain a global public health concern. The world has not yet come back to normal from the devastating effects of the highly contagious and pathogenic novel coronavirus, or Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Olfactory and taste dysfunction is common in patients infected by the novel coronavirus. In light of the emergence of different coronavirus variants, it is important to update the prevalence and pathophysiology of these side effects. In this review, articles published on the prevalence of olfactory and taste dysfunction from coronavirus disease (COVID-19) and their possible pathophysiologic mechanisms have been reviewed and reported. The modulatory role of different SARS-CoV-2 variants on the chemical senses is then described. The clinical relevance of chemical sense disorder and its long-term morbidity and management is also discussed.

Olfactory Dysfunction in Patients With Coronavirus Disease 2019: A Review

The coronavirus disease 2019 (COVID-19) pandemic is wreaking havoc on public-health and economic systems worldwide. Among the several neurological symptoms of patients with COVID-19 reported in clinical practice, olfactory dysfunction (OD) is the most common. OD occurs as the earliest or the only clinical manifestation in some patients. Increasing research attention has focused on OD, which is listed as one of the main diagnostic symptoms of severe acute respiratory syndrome-coronavirus-2 infection. Multiple clinical and basic-science studies on COVID-19-induced OD are underway to clarify the underlying mechanism of action. In this review, we summarize the clinical characteristics, mechanisms, evaluation methods, prognosis, and treatment options of COVID-19-induced OD. In this way, we hope to improve the understanding of COVID-19-induced OD to aid early identification and precise intervention.

Objective Evaluation of Olfactory and Taste Dysfunction Among COVID-19 Patients: A Cross Sectional Study from Tribal India

There is a varying prevalence of olfactory and taste dysfunction (OTD) in COVID-19 patients, with a higher prevalence reported in the European population as compared to the Asian population. Psychophysical tests are crucial to determine the exact frequency, extent and clinical characteristics of these OTDs. The present study objectively evaluated the OTD for patients treated in the Dedicated COVID-19 Hospital (DCH) in Shahdol. This prospective cross-sectional study was conducted after IEC approval in DCH Shahdol for a period of four months among RT-PCR positive patients, and they were evaluated using validated chemosensitive psychophysical test during ENT consultation to identify OTD. The sample size was calculated as 92 considering prevalence (p) of OTD as 41.3% by applying formula: n = (Z^1-a/2)² × p (1-p) / d ². The information pertaining to the subjects was kept anonymous and confidential. During data analysis, an association was significant for p value < 0.05. It was observed that 45.5% of subjects reported either loss of taste or smell. During objective evaluation, olfactory and taste dysfunction was observed among 42.4% of subjects (95/224). The Chi-square analysis reflected statistically significant difference (p < 0.05) between subjects with OTD and without OTD for the variables such as days from onset of symptoms to admission, and symptoms (fever, sore throat and shortness of breath). Taste and smell are among the important senses and in India they are mostly subjectively evaluated for COVID-19 induced OTD which results in underreporting of these symptoms. So, a gold standard objective evaluation should be taken into consideration to evaluate OTD.

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.

The D614G Virus Mutation Enhances Anosmia in COVID-19 Patients: Evidence from a Systematic Review and Meta-analysis of Studies from South Asia

The prevalence of chemosensory dysfunction in patients with COVID-19 varies greatly between populations. It is unclear whether such differences are due to factors at the level of the human host, or at the level of the coronavirus, or both. At the host level, the entry proteins which allow virus binding and entry have variants with distinct properties, and the frequency of such variants differs between ethnicities. At the level of the virus, the D614G mutation enhances virus entry to the host cell. Since the two virus strains (D614 and G614) coexisted in the first six months of the pandemic in most populations, it has been difficult to distinguish between contributions of the virus and contributions of the host for anosmia. To answer this question, we conducted a systematic review and meta-analysis of studies in South Asian populations when either the D614 or the G614 virus was dominant. We show that populations infected predominantly with the G614 virus had a much higher prevalence of anosmia (pooled prevalence of 31.8%) compared with the same ethnic populations infected mostly with the D614 virus strain (pooled anosmia prevalence of 5.3%). We conclude that the D614G mutation is a major contributing factor that increases the prevalence of anosmia in COVID-19, and that this enhanced effect on olfaction constitutes a previously unrecognized phenotype of the D614G mutation. The new virus strains that have additional mutations on the background of the D614G mutation can be expected to cause a similarly increased prevalence of chemosensory dysfunctions.

Incidence of Anosmia among Covid 19 patients in India

The pandemic COVID-19 has relentlessly caused havoc to human life since its outbreak in December 2019. The disease has been a challenge for all. The clinical manifestations of Covid-19 ranges from no symptoms at all to severe acute respiratory distress syndrome. Anosmia being one of the important clinical features of COVID-19 has always been overlooked by the Indian population. This formed the background for this study. Aim To identify the incidence of anosmia reported in COVID- 19 patients in India. Materials and Methods Literature search was carried out from January 2020 to March 2021 in databases like PUBMED and Google Scholar using the key words "ANOSMIA", "HYPOSMIA" and "OLFACTORY DYSFUNCTION" in conjunction with "COVID-19", "SARS-COV-2", and "CORONAVIRUS". Boolean operators were used to narrow and broaden the search. The search yielded sixteen eligible articles. Result The scrutiny of the 16 articles revealed an incidence range of anosmia from 9.2% to 82% and an average anosmia incidence rate of 30.19%. The cumulative incidence rate of anosmia in those studies where objective analysis was done is 52.2% and 16.4% for subjective analysis. Discussion The prevalence of anosmia in Indian population is found to be much lesser than that reported by European countries due to ethnicity or negligence. Objective evaluation of anosmia in COVID-19 patients increases the incidence of anosmia drastically. Hence objective evaluations such as UPIST, SNIFFING STICK test, etc. is to be promoted. This study also Emphasises the lack of common gold standard testing for olfaction like vision and hearing.

Prevalence and prognosis of otorhinolaryngological symptoms in patients with COVID-19: a systematic review and meta-analysis

Objective

A systematic review and meta-analysis were performed to evaluate the prevalence and prognosis of otorhinolaryngological symptoms in patients with the diagnosed coronavirus disease 2019 (COVID-19).

Methods

A systematic search of PubMed, Embase, Web of Science, and Google Scholar databases was performed up to August 19, 2020.We included studies that reported infections with COVID-19 and symptoms of otolaryngology. The retrieved data from the respective studies were evaluated and summarized. The study's immediate result was to assess the combined prevalence of otorhinolaryngological symptoms in patients with COVID-19. However, the secondary result was to determine the exacerbation of COVID-19 infection in patients with otorhinolaryngological symptoms.

Results

Fifty-four studies with 16,478 patients were included. Olfactory dysfunction, sneezing and sputum production were the 3 most prevalent otorhinolaryngological symptoms in patients with COVID-19. The pooled prevalence amongst the prevalent symptoms was 47% (95% CI 29–65; range 0–98; I² = 99.58%), 27% (95% CI 11–48; range 12–40; I² = 93.34%), and 22% (95% CI 16–30; range 2–56; I² = 97.60%), respectively. The proportion of severely ill patients with sputum production and shortness of breath was significantly higher among patients with COVID-19 infections (OR 1.66 [95% CI 1.08–2.54]; P = 0.02, I² = 51% and 3.29 [95% CI 1.57–6.90]; P = 0.002, I² = 49%, respectively). Subgroup analysis showed no statistically significant differences between the incidence of otolaryngology symptoms in severely ill patients and non-severely ill patients (OR 1.43 [95% CI 1.12–1.82]; P = 0.07 I² = 53.1%). In contrast, the incidence of shortness of breath in severely ill patients was significantly increased (3.29 [1.57–6.90]; P = 0.002, I² = 49%).

Conclusion

Our research shows that otorhinolaryngology symptoms in patients with COVID-19 are not uncommon, which should attract otorhinolaryngologists' attention.