Anosmia or Ageusia Following COVID-19 Vaccination: A Systematic Review

Aim: To systematically review the cases of anosmia or ageusia after receiving the coronavirus disease 2019 (COVID-19) vaccine. Methods: A systematic search was conducted in electronic databases, including Web of Science, Scopus, Embase, and PubMed, to identify any published study that evaluated the anosmia or ageusia after receiving the COVID-19 vaccine, including case reports, case series, letter to editor articles with reported cases regarding our topic, or observational studies with at least 1 eligible patient consisted with our criteria. We excluded the studies that reported anosmia or ageusia due to COVID-19 infection and non-COVID-19 vaccines. Results: Five studies consisting of 11 patients were included in this systematic review. Of the 11 patients, 5 patients had received the Pfizer COVID-19 vaccine and 6 patients received the Oxford-AstraZeneca COVID-19 vaccine, of which 6 patients developed symptoms after the first dose of vaccination and 5 patients were symptomatic after the second vaccine dose. Most of the patients developed symptoms within 1 week after the vaccination. The disorders of the patients included partial or total anosmia, parosmia, phantosmia, hyposmia, ageusia, and dysgeusia. Also, the patients had symptoms other than smell or taste disorders, including arthralgia, fever, chills, rhinorrhea, myalgia, abdominal pain, fatigue, muscle weakness, altered bowel pattern, aural fullness, tinnitus, and headache. Most of the evaluated patients did not receive any treatment as for their disorders. However, in some cases, treatment with oral corticosteroids or dietary supplementation was required. Conclusion: Anosmia and ageusia are important symptoms of COVID-19 vaccination. These symptoms will resolve without any treatment in most cases, although some interventions may be needed in some patients.

Quantitive Assessment of Gustatory Function and Its Association with Demographics, and Systemic Morbidity

This study aimed to analyze the associations of gustatory dysfunction as measured by validated taste strips with demographics and co-morbidities. This cross-sectional study retrospectively analyzed records of patients who attended the Orofacial Chemosensory Center of Hadassah Medical Center between 2017 and 2020. Taste strips were used as a validated method to determine taste dysfunction. A total of 272 subjects were included, 137 (50.4%) women and 135 (49.6%) men, with a mean age of 53.5 ± 19.3 years and age range of 18-98 years. The total taste score among the study population was 8.53 ± 4.03 (scale range 0-16). Age had a significant negative correlation with the total taste score (p = 0.001), and men exhibited worse total (p < 0.001), salty (p = 0.003), and bitter (p < 0.001) scores. Major trauma was associated with worse total (p < 0.001) and specialized taste assessments (sweet (p = 0.001), sour (p = 0.002), salty (p = 0.016), and bitter (p < 0.001)). Chemotherapy was associated with reduced total (p < 0.001), salty (p = 0.003), and bitter (p = 0.001) taste scores. Zinc deficiency exhibited worse salty (p = 0.027) and total (p = 0.038) taste scores. Patients with burning mouth syndrome (BMS) showed higher salty scores (p = 0.017). Patients who experienced exposure to toxic chemicals exhibited worse salty scores (p = 0.024). We conclude that gustatory dysfunction is associated with older age, male sex, and co-morbidities of major trauma, current chemotherapy, zinc deficiency, BMS, and exposure to toxins. The study highlights the importance of systemic evaluation and quantitive gustatory dysfunction assessment as part of the diagnostic process of patients with subjective complaints of taste disorders.

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.

Olfactory and gustatory disorders associated with SARS-CoV-2 infection in children and adults: a topic review

This paper is aimed at comprehensively reviewing olfactory and gustatory disorders caused by SARS-CoV-2 in children and adults. An electronic and manual search was done on three databases: MEDLINE, Embase, and Web of Science. Inclusion criteria included publications written in English, involving humans in the age range of 0 to 99 years that were captured by a controlled vocabulary of thesaurus terms. Olfactory and gustatory disorders rates in COVID-19 ranged from 22% to 71.9% in adults and 16.6% to 25.8% in children. Olfactory and gustatory disorders might appear as the first symptom, and in adults might even be the only symptom (4.8% to 10%). Anosmia is the most common olfactory disorder and hypogeusia is the most common gustatory disorder. In 33% to 89% of cases, olfactory and gustatory disorders resolve spontaneously within a few weeks, coinciding with the resolution of other COVID-19 symptoms, both in adults and children. However, in some patients, olfactory and gustatory disorders persist beyond the resolution of other symptoms. Notably, children generally experience a swifter and more favorable recovery compared to adults. The precise pathogenesis underlying olfactory and gustatory disorders in the context of COVID-19 remains unclear and is likely multifactorial. Presently, no established treatment protocol exists for olfactory and gustatory disorders and current treatments reviewed lack robust evidence and are not readily available for clinical use. Olfactory training represents the only therapy currently recommended by international authorities. Pediatric practitioners and general dental practitioners should be aware of olfactory and gustatory disorders in both pediatric and adult populations, including their biologic mechanisms, treatment options, and recovery rates.

Assessment of the Early Detection of Anosmia and Ageusia Symptoms in COVID-19 on Twitter: Retrospective Study

BACKGROUND

During the unprecedented COVID-19 pandemic, social media has been extensively used to amplify the spread of information and to express personal health-related experiences regarding symptoms, including anosmia and ageusia, 2 symptoms that have been reported later than other symptoms.

OBJECTIVE

Our objective is to investigate to what extent Twitter users reported anosmia and ageusia symptoms in their tweets and if they connected them to COVID-19, to evaluate whether these symptoms could have been identified as COVID-19 symptoms earlier using Twitter rather than the official notice.

METHODS

We collected French tweets posted between January 1, 2020, and March 31, 2020, containing anosmia- or ageusia-related keywords. Symptoms were detected using fuzzy matching. The analysis consisted of 3 parts. First, we compared the coverage of anosmia and ageusia symptoms in Twitter and in traditional media to determine if the association between COVID-19 and anosmia or ageusia could have been identified earlier through Twitter. Second, we conducted a manual analysis of anosmia- and ageusia-related tweets to obtain quantitative and qualitative insights regarding their nature and to assess when the first associations between COVID-19 and these symptoms were established. We randomly annotated tweets from 2 periods: the early stage and the rapid spread stage of the epidemic. For each tweet, each symptom was annotated regarding 3 modalities: symptom (yes or no), associated with COVID-19 (yes, no, or unknown), and whether it was experienced by someone (yes, no, or unknown). Third, to evaluate if there was a global increase of tweets mentioning anosmia or ageusia in early 2020, corresponding to the beginning of the COVID-19 epidemic, we compared the tweets reporting experienced anosmia or ageusia between the first periods of 2019 and 2020.

RESULTS

In total, 832 (respectively 12,544) tweets containing anosmia (respectively ageusia) related keywords were extracted over the analysis period in 2020. The comparison to traditional media showed a strong correlation without any lag, which suggests an important reactivity of Twitter but no earlier detection on Twitter. The annotation of tweets from 2020 showed that tweets correlating anosmia or ageusia with COVID-19 could be found a few days before the official announcement. However, no association could be found during the first stage of the pandemic. Information about the temporality of symptoms and the psychological impact of these symptoms could be found in the tweets. The comparison between early 2020 and early 2019 showed no difference regarding the volumes of tweets.

CONCLUSIONS

Based on our analysis of French tweets, associations between COVID-19 and anosmia or ageusia by web users could have been found on Twitter just a few days before the official announcement but not during the early stage of the pandemic. Patients share qualitative information on Twitter regarding anosmia or ageusia symptoms that could be of interest for future analyses.

The effectiveness of cerebrolysin, a multi-modal neurotrophic factor, for treatment of post-covid-19 persistent olfactory, gustatory and trigeminal chemosensory dysfunctions: a randomized clinical trial

BACKGROUND

This trial aimed to monitor the outcomes of persistent post-covid-19 smell and taste disorders after cerebrolysin therapy, a NTF, and olfactory and gustatory trainings.

RESEARCH DESIGN AND METHODS

This was a prospective randomized trial. It included 250 patients (male = 93, female = 157; age: 31.3 ± 8.9 years). Patients were randomized into group 1 (n = 150): received cerebrolysin [5 ml/d (IM), 5d/week] and practiced olfactory and gustatory trainings, and group 2 (n = 100): practiced olfactory and gustatory trainings only, for ≥ 8-24 weeks. Measures of outcomes were: a clinical questionnaire; sniffin' odor, taste and flavor identification tests; and global rating scales for smell and taste.

RESULTS

The duration of disorders was 11.7 ± 3.7mo (range: 6-24mo). The majority (n = 167; 66.8%) developed parosmia within months (3.6 ± 2.7mo) after anosmia. Objective testing showed anosmia in all and taste, flavor, and trigeminal sensory losses in 18% (n = 45). Analyses for secondary outcome were done on 202 patients (group 1 = 130; group 2 = 72). Recovery was complete in 61.5% (n = 80) with cerebrolysin therapy and partial in 17% (n = 22). There was no recovery with trainings only. There were no predictors for recovery.

CONCLUSIONS

Cerebrolysin had fast, promising, and constant effect, with cure rate of > 60%. This might be due to its ability to initiate and enhance neuronal regeneration and reorganization of sensory epithelia.

TRIAL REGISTRATION

NCT04830943.

Prevalence of Self-Reported Anosmia and Ageusia in Elderly Patients Who Had Been Previously Hospitalized by SARS-CoV-2: The LONG-COVID-EXP Multicenter Study

We explored two different graph methods for visualizing the prevalence of self-reported post-COVID anosmia and ageusia in a large sample of individuals who had been previously hospitalized in five different hospitals. A cohort of 1266 previously hospitalized COVID-19 survivors participated. Participants were assessed at hospitalization (T0) and at three different follow-up periods: 8.4 (T1), 13.2 (T2), and 18.3 (T3) months after hospital discharge. They were asked about the presence of self-reported anosmia and ageusia that they attributed to infection. Anosmia was defined as a self-perceived feeling of complete loss of smell. Ageusia was defined as a self-perceived feeling of complete loss of taste. Data about hospitalization were recorded from medical records. The results revealed that the prevalence of anosmia decreased from 8.29% (n = 105) at hospitalization (T0), to 4.47% (n = 56) at T1, to 3.27% (n = 41) at T2, and 3.35% (n = 42) at T3. Similarly, the prevalence of ageusia was 7.10% (n = 89) at the onset of SARS-CoV-2 infection (T0), but decreased to 3.03% (n = 38) at T1, to 1.99% (n = 25) at T2, and 1.36% (n = 17) at T3. The Sankey plots showed that only 10 (0.8%) and 11 (0.88%) patients exhibited anosmia and ageusia throughout all the follow-ups. The exponential curves revealed a progressive decrease in prevalence, demonstrating that self-reported anosmia and ageusia improved in the years following hospitalization. The female sex (OR4.254, 95% CI 1.184-15.294) and sufferers of asthma (OR7.086, 95% CI 1.359-36.936) were factors associated with the development of anosmia at T2, whereas internal care unit admission was a protective factor (OR0.891, 95% CI 0.819-0.970) for developing anosmia at T2. The use of a graphical method, such as a Sankey plot, shows that post-COVID self-reported anosmia and ageusia exhibit fluctuations during the first years after SARS-CoV-2 infection. Additionally, self-reported anosmia and ageusia also show a decrease in prevalence during the first years after infection, as expressed by exponential bar plots. The female sex was associated with the development of post-COVID anosmia, but not ageusia, in our cohort of elderly patients previously hospitalized due to COVID-19.

Efficacy of Stellate Ganglion Block in Treating Long-Term COVID-19-Related Olfactory and Gustatory Dysfunction: A Case Series

Olfactory and gustatory dysfunction, including anosmia, parosmia, ageusia, and dysgeusia, are common long-term symptoms of coronavirus disease 2019 (COVID-19) infection. These symptoms can have a severe impact on quality of life of a patient, including psychological well-being. Stellate ganglion block (SGB) has recently been explored as a potential therapeutic intervention for these symptoms. In this case series, we present six patients with long-term COVID-19 symptoms and we detail how their symptoms evolved after an SGB. All SGB were performed under ultrasound guidance by the same physician. Patients had a right SGB during the initial visit, followed by a left SGB at a subsequent visit. All but one patient reported improvements in olfaction and gustation after the SGB. Our findings suggest that SGB may be a promising therapeutic intervention for patients with olfactory and gustatory dysfunction related to long-term COVID-19 symptoms. Further research is needed to confirm these findings and to explore the optimal treatment protocol.

Prevalence of Chemosensitive Neurological Disorders of Smell and Taste and Association with Blood Groups in SARS-CoV-2 Patients: Cross-Sectional Study

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has caused a highly challenging and threatening situation worldwide. SARS-CoV-2 patients develop various clinical symptoms. The olfactory and taste dysfunctions are potential neurological manifestations among SARS-CoV-2 patients; however, their relationship with blood groups has rarely been investigated. This study aimed to investigate the prevalence of chemosensitive neurological disorders of smell and taste and their association with blood groups in SARS-CoV-2 patients. The present cross-sectional study was performed in the Department of Pathology, and Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia. A well-structured, self-administered questionnaire was designed and distributed through social media platforms. A total of 922 Saudi and non-Saudi adults aged 18 years or older participated in the study. Out of 922 participants, the number of people who had anosmia was 309 (33.5%), 211 (22.9%) had hyposmia, and 45 (4.8%) had dysosmia. Moreover, 180 (19.52%) had ageusia, 47 (5.1%) and 293 (31.8%) had hypogeusia and dysgeusia, respectively. Among all the participants, 565 (61.27%) had smell-related disorders and 520 (56.39%) participants had taste-related clinical symptoms. The occurrence of anosmia and ageusia was relatively high among females compared to males (p = 0.024). The prevalence of smell-related disorders was 25.0% (230) and taste-related disorders was 23.21% (214) among the study participants with blood group O compared to all other blood group (A, B, and AB) participants who have smell allied disorders 30.69% (283), and taste allied disorders 27.98% (258). The prevalence of chemosensitive neurological disorders involving impaired smell and taste was higher in SARS-CoV-2 patients. These clinical symptoms were common among the participants with blood group type O compared to all other ABO blood group types. The role of certain demographic characteristics was consistent throughout multiple studies, notably with female gender and young adults.

Oral manifestations associated with Novel Coronavirus Disease - 2019 (COVID-19): A questionnaire based hypothetical study

Background: Since the Coronavirus disease 2019 (COVID-19) outbreak in 2019, the virus has evolved drastically, presenting with sets of mutations that influence its properties, including transmissibility and antigenicity. The oral mucosa is postulated as probable portal entry and several oral manifestations have been identified, which places dental professionals in a position to recognize probable COVID-19 patients depending on oral signs and symptoms in the initial phases of the disease itself. As co-existing with COVID-19 seems to be a new reality, greater understanding is required regarding early oral signs and symptoms which can be predictors for timely intervention and prevention of complications in COVID-19 patients. The objective of the study is to identify the distinguishing oral signs and symptoms among COVID-19 patients and to establish possible correlation between severity of COVID-19 infection and oral symptoms. Methods: This study recruited 179 ambulatory, non-hospitalized COVID-19 patients from the Kingdom of Saudi Arabia's Eastern Province's designated hotels for COVID-19 and home isolated patients from the same region using a convenience sample method. Data was collected by qualified and experienced investigators, including two physicians and three dentists, using a validated comprehensive questionnaire through telephonic interviews with the participants. The X ² was used to assess the categorical variables, and odd's ratio was calculated to determine the strength of the association between general symptoms and oral manifestations. Results: Oral and nasopharyngeal lesions or conditions like loss of smell and taste, xerostomia, sore throat, and burning sensation were predictors of COVID-19-related systemic symptoms such as cough, fatigue, fever, and nasal congestion were identified to be statistically significant (p<0.05). Conclusions: The study reveals the occurrence of olfactory or taste dysfunction, dry mouth, sore throat, and burning sensation along with COVID-19 generic symptoms, should be considered as suggestive yet not conclusive indicators of COVID-19.

The Revived Interest in Ageusia Research during the COVID-19 Pandemic: A Bibliometric Analysis

The evolution of ageusia research literature has yet to be investigated. This bibliometric study analyzed the entire ageusia research literature indexed in Web of Science, to reveal its growth and the most productive entities in terms of authors, institutions, countries, journals, and journal categories. In addition, this study aimed to identify medical conditions (and their treatments) that were frequently associated with ageusia. On 7 March 2022, the Web of Science Core Collection database was accessed with the following search query: TS = (ageusia OR "taste loss" OR "loss of taste" OR "loss of gustat*" OR "gustatory loss"). The search identified publications mentioning these terms in their title, abstract, or keywords. No additional filters were placed on publication year, language, etc. The basic publication and citation counts were extracted from the in-built functions of the database. The complete record of the publications was exported into VOSviewer, a bibliometric software for visualizations. The search yielded 1170 publications. The cumulative publication and citation counts of the ageusia research sharply increased in 2020. The most productive author was Professor Thomas Hummel from Technische Universität Dresden. Ageusia research had heavy contributions from the United States, Italy, the United Kingdom, Germany, and India. The top 5 most productive journals mainly belonged to the otorhinolaryngology and medicine categories. The medical conditions frequently investigated in ageusia research included COVID-19, cancers (head and neck, and advanced basal cell), Guillain-Barré syndrome, neurodegenerative diseases, diabetes, and Sjogren's syndrome. This study could act as a begvinner's guide for (1) clinicians who are not familiar with ageusia so that they might better understand which scenarios they need to be more aware of since ageusia could be a co-morbidity of a patient's underlying disease, and (2) for those who wish to search for relevant authors and journals for suitable publications related to the topic.

Olfactory and Gustatory Dysfunctions Following COVID-19 Infection: Factors That Affect Their Duration in Saudi Arabia

INTRODUCTION

 Many people infected with coronavirus disease 2019 (COVID-19) have developed post-COVID-19 symptoms, which are defined as symptoms and signs (e.g., anosmia and ageusia) that persist for more than 12 weeks after getting infected with COVID-19. These symptoms may appear after or during the infection and cannot be explained by any alternative disease. In this study, we aim to investigate the factors that affect the duration of anosmia and ageusia in Saudi Arabia.

METHODS

 We conducted a nationwide, cross-sectional study using an online survey in Saudi Arabia from 14 February 2022 to 23 July 2022. The electronic survey was distributed using social media platforms, such as Twitter, WhatsApp, and Telegram.

RESULT

 The study enrolled 2497 individuals who were infected with COVID-19. A total of 60.1% of the participants showed symptoms of anosmia, ageusia, or both after getting infected with COVID-19. According to our data, we found that being a female and not having a repeated COVID-19 infection were risk factors (independent predictors) of the long duration of anosmia after COVID-19 recovery (p = <0.05). While being a male patient, a smoker, and being admitted to the ICU were risk factors (independent predictors) of long duration of ageusia after COVID-19 recovery (p = <0.05).

CONCLUSION

 In conclusion, the prevalence of chemosensory dysfunction symptoms, both olfactory and gustatory, after COVID-19 infection among the Saudi population was high. However, several factors can influence their duration, including gender, smoking, and severity of the infection.

Viral Shedding and Persistence of Anosmia and Ageusia in an Asymptomatic SARS-CoV-2 Infection

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), first identified in the region of Wuhan, China is responsible for the ongoing pandemic of coronavirus disease-19 (COVID-19) that has been a part of our life for almost three years now. Although there have been multiple reports of prolonged viral shedding in people with severe disease, viral shedding lasting for extended periods can occur in patients with less serious clinical insults or even asymptomatic individuals. Herein, we report a case of a female patient that, although otherwise asymptomatic, remained positive on nasopharyngeal viral testing for a prolonged period, alongside persisting complaints of anosmia and ageusia. The patient may well have been one of the first individuals to be infected in the Greek territory; we followed up on her long-term COVID sequelae from the time of proof of infection up until the present day.

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.

Covid-19 affects taste independently of smell: results from a combined chemosensory home test and online survey from a global cohort (N=10,953)

People often confuse smell loss with taste loss, so it is unclear how much gustatory function is reduced in patients self-reporting taste loss. Our pre-registered cross-sectional study design included an online survey in 12 languages with instructions for self-administering chemosensory tests with ten household items. Between June 2020 and March 2021, 10,953 individuals participated. Of these, 3,356 self-reported a positive and 602 a negative COVID-19 diagnosis (COVID+ and COVID-, respectively); 1,267 were awaiting test results (COVID?). The rest reported no respiratory illness and were grouped by symptoms: sudden smell/taste changes (STC, N=4,445), other symptoms excluding smell or taste loss (OthS, N=832), and no symptoms (NoS, N=416). Taste, smell, and oral irritation intensities and self-assessed abilities were rated on visual analog scales. Compared to the NoS group, COVID+ was associated with a 21% reduction in taste (95% Confidence Interval (CI): 15-28%), 47% in smell (95%-CI: 37-56%), and 17% in oral irritation (95%-CI: 10-25%) intensity. In all groups, perceived intensity of smell (r=0.84), taste (r=0.68), and oral irritation (r=0.37) was correlated. Our findings suggest most reports of taste dysfunction with COVID-19 were genuine and not due to misinterpreting smell loss as taste loss (i.e., a classical taste-flavor confusion). Assessing smell and taste intensity of household items is a promising, cost-effective screening tool that complements self-reports and helps to disentangle taste loss from smell loss. However, it does not replace standardized validated psychophysical tests.

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.

Covid-19 affects taste independent of taste-smell confusions: results from a combined chemosensory home test and online survey from a large global cohort

People often confuse smell loss with taste loss, so it is unclear how much gustatory function is reduced in patients self-reporting taste loss. Our pre-registered cross-sectional study design included an online survey in 12 languages with instructions for self-administering chemosensory tests with 10 household items. Between June 2020 and March 2021, 10,953 individuals participated. Of these, 5,225 self-reported a respiratory illness and were grouped based on their reported COVID test results: COVID-positive (COVID+, N = 3,356), COVID-negative (COVID-, N = 602), and COVID unknown for those waiting for a test result (COVID?, N = 1,267). The participants who reported no respiratory illness were grouped by symptoms: sudden smell/taste changes (STC, N = 4,445), other symptoms excluding smell or taste changes (OthS, N = 832), and no symptoms (NoS, N = 416). Taste, smell, and oral irritation intensities and self-assessed abilities were rated on visual analog scales. Compared to the NoS group, COVID+ was associated with a 21% reduction in taste (95% confidence interval (CI): 15-28%), 47% in smell (95% CI: 37-56%), and 17% in oral irritation (95% CI: 10-25%) intensity. There were medium to strong correlations between perceived intensities and self-reported abilities (r = 0.84 for smell, r = 0.68 for taste, and r = 0.37 for oral irritation). Our study demonstrates that COVID-19-positive individuals report taste dysfunction when self-tested with stimuli that have little to none olfactory components. Assessing the smell and taste intensity of household items is a promising, cost-effective screening tool that complements self-reports and may help to disentangle taste loss from smell loss. However, it does not replace standardized validated psychophysical tests.

Physiological discrimination and correlation between olfactory and gustatory dysfunction in long-term COVID-19

The spread of the SARS-CoV-2 virus produces a new disease termed COVID-19, the underlying physiological mechanisms of which are still being understood. Characteristic of the infection is the compromising of taste and smell. There is a persistent need to discriminate the dysfunctions and correlation between taste and smell, which are probably epiphenomena of other concealed conditions. Anosmic and ageusic long-term COVID-19 patients were re-evaluated after 1 year using a Volabolomic approach with an e-nose recording system coupled with olfactometric and gustometric tests. Here a range of sensory arrangements was found, from normal taste and smell to complete losses. The following patterns of olfactory threshold (OT)-taste threshold-olfactory uni- and cross-modal perception were found anosmia-severe hypogeusia-anosmia; hyposmia-hypogeusia-severe hyposmia; normosmia-ageusia-hyposmia; severe hyposmia -normogeusia-normosmia. There is a strong correlation between OT and olfactory uni- and cross-modal perception, a moderate correlation between olfactory and taste threshold and no correlation between OT and taste threshold. In conclusion, this study provides evidence for the feasibility of testing the chemical senses to directly objectify function in order to discriminate taste from olfactory impairment. Furthermore, it allows to hypothesize a long-term effect of the virus due to neuroinvasion through, probably, the olfactory system with injury in the related multisensory areas of taste and smell.

Evolution of throat symptoms during the COVID-19 pandemic in the US

OBJECTIVES

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) structure and host tropism have changed over time, and so has the involvement of throat structures. This infodemiological analysis is hence aimed at investigating the evolution of throat symptoms during the COVID-19 pandemic in the US.

METHODS

We searched Google Trends using the medical search terms "ageusia", "hoarseness", "dysphonia", "pharyngitis" and "laryngitis", setting geographical location to "United States", within the past 5 years. The weekly Google Trends score for these symptoms, which reflects their national Web popularity, was divided in three parts, as "pre-COVID" (July 2017 to February 2020), COVID-19 "pre-Omicron" (March 2020 to November 2021), and COVID-19 "Omicron" (December 2021 to July 2022), and then compared.

RESULTS

The volume of searches for ageusia increased in the pre-Omicron period and remained significantly higher also during Omicron prevalence, though a significant decrease (∼30%) occurred with Omicron lineages compared to previous strains. The Google searches for hoarseness and dysphonia were relatively similar between the pre-COVID and pre-Omicron periods, but then significantly increased during Omicron predominance. The Google searches for pharyngitis and laryngitis decreased in the pre-Omicron period, but then considerably increased following Omicron emergence. Omicron endemic spread could be significantly and independently predicted by the volume of searches for pharyngitis, laryngitis and hoarseness.

CONCLUSIONS

The epidemiological burden of throat symptoms has considerably changed after Omicron emergence, with a lower likelihood of developing chemosensory dysfunctions and enhanced risk of throat involvement.

Prevalence, Patterns, Prognosis, and Psychosocial Impact of Olfactory and Gustative Dysfunctions Among Saudi COVID-19 Patients

Objective The objective of this study is to estimate the prevalence of olfactory and gustative dysfunctions (OGD) and analyze their pattern and psychosocial impact among COVID-19 patients. Method A cross-sectional study was conducted among 194 confirmed COVID-19 cases at Al-Noor Specialist Hospital between 1 September 2020 and 30 September 2021. A questionnaire was translated and modified from another study to collect the baseline demographic data and medical history; characterization of smell and taste loss separately, including timing, level, practices or treatment used to restore, recovery, and symptom duration; and the psychological impact of OGD using six items to explore the multidimensional impact, such as daily activity, job performance, and social life. A four-point Likert-type agreement scale was used, and an impact score was calculated. Result As high as 97.4% and 94.8% of the participants declared having experienced a certain level of olfactory and gustative dysfunction, respectively. In the majority of these cases, the dysfunction occurred after the acute phase of the disease and persisted less than one month after onset. Social life (78.4%), job performance (64.4%), and daily life activities (42.8%) were the most frequently impacted dimensions, and 32% of the participants were deemed to have experienced a high psychosocial impact. Younger participants, females, and certain job categories were significantly more impacted than their counterparts. Conclusion OGDs are highly frequent in COVID-19 patients. They are described to be relatively severe and have frequent psychosocial impacts, notably in females and the younger age category. Further research is warranted to determine efficacious preventive and management strategies in order to prevent their long-term impact on wellbeing.

A Shift in SARS-CoV-2 Omicron Variant's Entry Pathway Might Explain Different Clinical Outcomes

Globally, SARS CoV-2 omicron variant has led to a notable increase of COVID-19 diagnoses, although with less severe clinical manifestations and decreased hospitalizations. The omicron wave swelled faster than previous waves, completely displacing the delta variant within weeks, and creating worldwide concern about final, successful pandemic control. Some authors contend that symptoms associated to omicron differ from 'traditional' symptoms and more closely resemble those of the common cold. One major COVID-19 symptom frequent with other variants-loss of taste and smell-is rarely present with omicron. This may be of interest, since it has also been suggested that direct SARS-CoV-2 invasion into the brainstem through the olfactory nerves by transsynaptic pathways could provide one explanation for the acute respiratory distress syndrome refractory to treatment. Brainstem infection by SARS-CoV-2 can severely damage the respiratory center, triggering functional deviations that affect involuntary respiration, leading to acute respiratory distress syndrome refractory to treatment, the main cause of death in COVID-19 patients. A shift in the omicron SARS-CoV-2 entry pathway from cell-surface fusion, triggered by TMPRSS2, to cathepsin-dependent fusion within the endosome, may affect transmission, cellular tropism and pathogenesis. Therefore, we can hypothesize that this entrance modification may impact transmission from the olfactory nerve to the brainstem through transsynaptic pathways. A decrement of the virus's direct invasion into the brainstem could diminish respiratory center dysfunction, reducing acute respiratory distress syndrome and the need for mechanical ventilation.

Prevalence of Anosmia in 10.157 Pediatric COVID-19 Cases: Multicenter Study from Turkey

INTRODUCTION

COVID-19-related anosmia is a remarkable and disease-specific finding. With this multicenter cohort study, we aimed to determine the prevalence of anosmia in pediatric cases with COVID-19 from Turkey and make an objective assessment with a smell awareness questionnaire.

MATERIAL AND METHODS

This multicenter prospective cohort study was conducted with pediatric infection clinics in 37 centers in 19 different cities of Turkey between October 2020 and March 2021. The symptoms of 10.157 COVID-19 cases 10-18 years old were examined. Age, gender, other accompanying symptoms, and clinical severity of the disease of cases with anosmia and ageusia included in the study were recorded. The cases were interviewed for the smell awareness questionnaire at admission and one month after the illness.

RESULTS

Anosmia was present in 12.5% (1.266/10.157) of COVID-19 cases 10-18 years of age. The complete records of 1053 patients followed during the study period were analyzed. The most common symptoms accompanying symptoms with anosmia were ageusia in 885 (84%) cases, fatigue in 534 cases (50.7%), and cough in 466 cases (44.3%). Anosmia was recorded as the only symptom in 84 (8%) of the cases. One month later, it was determined that anosmia persisted in 88 (8.4%) cases. In the smell awareness questionnaire, the score at admission was higher than the score one month later (P < 0.001).

DISCUSSION

With this study, we have provided the examination of a large case series across Turkey. Anosmia and ageusia are specific symptoms seen in cases of COVID-19. With the detection of these symptoms, it should be aimed to isolate COVID-19 cases in the early period and reduce the spread of the infection. Such studies are important because the course of COVID-19 in children differs from adults and there is limited data on the prevalence of anosmia.

Testing for anosmia and ageusia in patients presenting to the emergency department with suspected coronavirus disease 2019 in Saudi Arabia

Objective

This study investigated the role of objective olfactory dysfunction (OD) and gustatory dysfunction (GD) testing among patients with suspected coronavirus disease 2019 (COVID-19) who presented with respiratory symptoms.

Methods

A prospective, blinded, observational study was conducted in the emergency units of two tertiary hospitals. Participants were asked to identify scents in the pocket smell test (PST) and flavors in four different solutions in the gustatory dysfunction test (GDT). We assessed the level of agreement between objective findings and self-reported symptoms. We evaluated the diagnostic accuracy of chemosensory dysfunction for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Results

Of 250 participants, 74 (29.6%) were SARS-CoV-2-positive. There was slight agreement between self-reported symptoms and objective findings (kappa = 0.13 and 0.10 for OD and GD, respectively). OD assessed by the PST was independently associated with COVID-19 (adjusted odds ratio = 1.89, 95% confidence interval, 1.04–3.46). This association was stronger when OD was combined with objective GD, cough, and fever (adjusted odds ratio = 7.33, 95% confidence interval, 1.17–45.84).

Conclusions

Neither the PST nor GDT alone are useful screening tools for COVID-19. However, a diagnostic scale based on objective OD, GD, fever, and cough may help triage patients with suspected COVID-19.

Varied Effects of COVID-19 Chemosensory Loss and Distortion on Appetite: Implications for Understanding Motives for Eating and Drinking

A common symptom of COVID-19 is altered smell and taste. This qualitative study sought to further characterise this altered chemosensory perception and its effects on appetite for food and drink. Eighteen women and two men who had experienced chemosensory loss associated with COVID-19 participated in semi-structured interviews. Thematic analysis of the interview transcripts revealed five major themes. These confirmed that all participants had experienced an altered sense of smell (anosmia, and less frequently parosmia and phantosmia) of variable duration. Loss of taste (ability to detect sweetness, saltiness, etc.) was less common. Participants experienced decreased, no change or increased appetite, with six participants reporting weight loss. Consistent with evidence linking diminished appetite with inflammation, for two participants, decreased appetite preceded anosmia onset. Anosmia reduced enjoyment of food and drink. Compensatory strategies included choosing salty, sweet and ‘spicy’ foods, and increased attention to food texture, and there was evidence that the postingestive rewarding effects of food intake were also important for maintaining appetite. Some participants mentioned increased alcohol intake, in part facilitated by reduced intensity of disliked flavours of alcoholic drinks. The narratives also underlined the value placed on the sociability and structuring of time that daily meals provide. This research adds to the record and analysis of lived experiences of altered chemosensory perception resulting from SARS-CoV-2 infection, and it contributes insights concerning the role of smell and flavour in motivating and rewarding food ingestion.

The effect of starting a meal with salt and date palm on taste impairment caused by COVID-19

BACKGROUND AND PURPOSE

This study was conducted to examine the effect of starting a meal with salt and date palm on the sense of taste in COVID-19 patients.

METHODS

This study was conducted using a randomized controlled method. Patient and disease information forms and Visual Analog Scale were used for data collection. Salt and date palm were used to stimulate the sense of taste in two different experimental groups. No procedure was made in the control group except for the practice of the clinic. The results were analyzed using SPSS version 25.

RESULTS

The mean ages of all groups were between 43.42 ± 8.60 and 47.22 ± 12.04 years. Fever, sore throat, dry mouth, cough, muscle weakness, and similar symptoms were present in all groups. Significant improvements were found in patients with hypoageusia and ageusia after date palm and salt application (p<0.01).

CONCLUSION

For taste impairment caused by COVID-19, consumption of date palm and tasting very little salt for therapeutic purposes may help to alleviate taste impairment. Based on the data obtained from this study, the pathophysiology of the effects of date palm and salt on taste complications should be investigated.

Investigation on the Factors Associated with the Persistence of Anosmia and Ageusia in Saudi COVID-19 Patients

The Coronavirus Disease 2019 (COVID-19) outbreak caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) resulted in a worldwide pandemic of a highly infectious disease. The difficulty of dealing with COVID-19 is the broad spectrum of clinical manifestations that involves various pathophysiological mechanisms, severities, duration, and complications. This study aims to help emphasize the factors related to the persistence and duration of anosmia (loss of smell) and ageusia (loss of taste) as part of post-acute COVID-19 syndrome in Saudi COVID-19 patients via a retrospective cross-sectional design. Eight hundred and eighty-one participants were recruited between March and April 2021. Those participants were 18 years or older, recovered from the COVID-19 infection, and completed 14 days after the onset of the acute phase of the disease. Among the 881 recruited participants, 808 have submitted eligible responses and were included in data analyses. The most common persistent symptoms in post-acute COVID-19 syndrome were anosmia (33.8%) and ageusia (26.4%). The data also showed a significant association between female sex and the incidence and the persistence of anosmia and ageusia. In multivariable analysis, anosmia during the acute phase was associated with BMI, asthma and shortness of breath, while anosmia during the post-acute phase was associated with sex. Ageusia during the acute phase was associated with sex, myalgia and arthralgia, while ageusia in the post-acute phase was associated with sex.

Development of restrictive eating disorders in children and adolescents with long-COVID-associated smell and taste dysfunction

BACKGROUND

Absent or abnormal senses of smell and taste have been frequently reported during both acute and long COVID in adult patients. In contrast, pediatric patients who test positive for SARS-CoV-2 are often asymptomatic and the loss of smell and/or taste has been infrequently reported. After observing several young patients with COVID-associated anosmia and ageusia at our clinic, we decided to investigate the incidence of subsequent eating disorders in these patients and in SARS-CoV-2 positive patients who did not experience anosmia and ageusia during the same period.

MATERIAL AND METHODS

A single-site retrospective cohort study of 84 pediatric patients with suspected long COVID who were treated in the Pediatric Infectious Diseases Outpatient Clinic at the University Hospital Essen were evaluated for persistent symptoms of COVID-19. Smell and taste dysfunction as well as eating behaviors were among the signs and symptoms analyzed in this study.

RESULTS

24 out of 84 children and adolescents described smell and taste dysfunction after confirmed or suspected SARS-CoV-2 infections. A large number of these patients (6 out of 24) demonstrated increased fixation on their eating behavior post-COVID and over time these patients developed anorexia nervosa.

DISCUSSION/CONCLUSION

In this study we saw a possible association of long-lasting post-COVID smell and taste dysfunction with subsequent development of eating disorders. This observation is worrisome and merits further investigation by healthcare providers at multiple clinical sites.

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.

COVID-19, anosmia, and ageusia in atopic children

More than a year and a half after the beginning of the coronavirus disease 2019 (COVID-19) pandemic, symptoms, such as loss of smell and taste (anosmia and ageusia, respectively), remain difficult to characterize and quantify, especially in children, since no validated tests to assess these disorders are available. However, these symptoms can also be seen in children, although less frequently than observed in the adult population. In this article, we present the results of a national survey that collected the responses of 267 Italian pediatricians on the presence of anosmia and ageusia in children affected by COVID-19. These data were then compared with existing literature.

Factors associated with anosmia recovery rate in COVID-19 patients

Objectives

The present study aimed to assess the 4- and 8-week recovery rate of anosmia and determine the factors associated with recovery in COVID-19 patients.

Method

This retrospective study was conducted from December 2020 to March 2021. RT-PCR-proven COVID-19 adult patients (over 18 years of age) with a positive history of anosmia were included in this study. Anosmia was assessed based on the COVID-19 Anosmia Reporting Tool. The recovery rate of anosmia after 4 and 8 weeks were evaluated, and the relationship between the patients' recovery and their clinical and demographic data was assessed.

Results

A total of 235 patients were included. Their mean age (±SD) was 43.95 ± 15.27 years. Anosmia recovery was reported in 207(88.51%) and 219 (93.19%) participants till 4 and 8 weeks. The mean recovery time was 19.42 ± 8.81 days. The result of logistic regression showed that smoking (P = .031; OR = 10.813), ageusia (P = .002; OR = 5.340), headache (P = .006; OR = 0.243), and nasal discharge (P < .001; OR = 0.080) were significantly associated with 4 weeks anosmia recovery. The only risk factor which was associated with a lower rate of 8 weeks anosmia recovery was presence of nasal discharge (OR = 0.106, P = .002).

Conclusion

The only risk factor which was associated with a lower rate of 8 weeks anosmia recovery was presence of nasal discharge. Our result demonstrated that although smoking was associated with higher recovery rate till 4 weeks, it could not be considered as a protective factor after 8 weeks. More studies are recommended to investigate the relationship between anosmia and the associated factors by consideration of both short- and long-term recovery rates and assess the possible mechanisms that could justify this association.

Levels of Evidence

3b.

Exploring the Clinical Utility of Gustatory Dysfunction (GD) as a Triage Symptom Prior to Reverse Transcription Polymerase Chain Reaction (RT-PCR) in the Diagnosis of COVID-19: A Meta-Analysis and Systematic Review

BACKGROUND

The diagnosis of COVID-19 is made using reverse transcription polymerase chain reaction (RT-PCR) but its sensitivity varies from 20 to 100%. The presence of gustatory dysfunction (GD) in a patient with upper respiratory tract symptoms might increase the clinical suspicion of COVID-19.

AIMS

To perform a systematic review and meta-analysis to determine the pooled sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR-) and diagnostic odds ratio (DOR) of using GD as a triage symptom prior to RT-PCR.

METHODS

PubMed and Embase were searched up to 20 June 2021. Studies published in English were included if they compared the frequency of GD in COVID-19 adult patients (proven by RT-PCR) to COVID-19 negative controls in case control or cross-sectional studies. The Newcastle-Ottawa scale was used to assess the methodological quality of the included studies.

RESULTS

21,272 COVID-19 patients and 52,298 COVID-19 negative patients were included across 44 studies from 21 countries. All studies were of moderate to high risk of bias. Patients with GD were more likely to test positive for COVID-19: DOR 6.39 (4.86-8.40), LR+ 3.84 (3.04-4.84), LR- 0.67 (0.64-0.70), pooled sensitivity 0.37 (0.29-0.47) and pooled specificity 0.92 (0.89-0.94). While history/questionnaire-based assessments were predictive of RT-PCR positivity (DOR 6.62 (4.95-8.85)), gustatory testing was not (DOR 3.53 (0.98-12.7)). There was significant heterogeneity among the 44 studies (I2 = 92%, p < 0.01).

CONCLUSIONS

GD is useful as a symptom to determine if a patient should undergo further testing, especially in resource-poor regions where COVID-19 testing is scarce. Patients with GD may be advised to quarantine while repeated testing is performed if the initial RT-PCR is negative.

FUNDING

None.

New Onset of Smell and Taste Loss Are Common Findings Also in Patients With Symptomatic COVID-19 After Complete Vaccination

The aim of this study is to investigate the clinical profile of patients who developed coronavirus disease 2019 (COVID‐19) after full vaccination. Demographic, epidemiological and clinical data were collected through medical records and online patient‐reported outcome questionnaire from patients who developed symptomatic SARS‐CoV‐2 infection, confirmed by nasopharyngeal swab, at least 2 weeks after completion of vaccination. A total of 153 subjects were included. The most frequent symptoms were: asthenia (82.4%), chemosensory dysfunction (63.4%), headache (59.5%), runny nose (58.2%), muscle pain (54.9%), loss of appetite (54.3%), and nasal obstruction (51.6%). Particularly, 62.3% and 53.6% of subjects reported olfactory and gustatory dysfunction, respectively. Symptom severity was mild or moderate in almost all cases. Chemosensory dysfunctions have been observed to be a frequent symptom even in subjects who contracted the infection after full vaccination. For this reason, the sudden loss of smell and taste could continue to represent a useful and specific diagnostic marker to raise the suspicion of COVID‐19 even in vaccinated subjects. In the future, it will be necessary to establish what the recovery rate is in these patients.

The taste of the pandemic-contemporary review on the current state of research on gustation in coronavirus disease 2019 (COVID-19)

Subjectively perceived impairment of taste is a common and distinct symptom of coronavirus disease 2019 (COVID-19). Large meta-analyses identified this symptom in approximately 50% of cases. However, this high prevalence is not supported by blinded and validated psychophysical gustatory testing, which showed a much lower prevalence in up to 26% of patients. This discrepancy may be due to misinterpretation of impaired retronasal olfaction as gustatory dysfunction. In addition, we hypothesized that COVID-19-associated hyposmia is involved in the decrease of gustatory function, as found for hyposmia of different origin. This indirect mechanism would be based on the central-nervous mutual amplification between the chemical senses, which fails in COVID-19-associated olfactory loss. However, further research is necessary on how severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) may directly impair the gustatory pathway as well as its subjective perception.

Turmeric as a Possible Treatment for COVID-19-Induced Anosmia and Ageusia

The coronavirus disease 2019 (COVID-19) pandemic has caused a calamitous perturbation of society worldwide. Anosmia and ageusia (or hyposmia and dysgeusia) have been recognized as two common expressions of COVID-19 infection that linger for days to weeks, and in rare cases are thought to be immutable. Time alone has hitherto proven most effective in their restoration, but turmeric, long believed by some to have medicinal properties, may be a swifter and surer alleviator of anosmia and ageusia. This case series reports the speedy and consequential restoration of taste and smell in two subjects infected with COVID-19 following ingestion of one 1000 mg dose of a turmeric supplement. In view of this, we propose that turmeric be considered in the treatment of anosmia and ageusia caused by COVID-19 infection.

COVID-19-Associated Parosmia and Dysgeusia: A Case Series

Impairment of the chemical senses - smell, taste, and chemesthesis - has been pinpointed as one of the main clinical presentations of coronavirus disease 2019 (COVID-19). Chemosensory dysfunction can be quantitative, involving reduction or loss of perception (e.g., hyposmia, anosmia, hypogeusia), and qualitative, involving distortion of perception (parosmia and dysgeusia). Quantitative chemosensory dysfunction is reported more often among COVID-19 patients than qualitative dysfunction. The following report details four patients with a laboratory-assisted diagnosis of COVID-19 who experienced qualitative chemosensory dysfunction. A discussion of these symptoms in the broader context of upper respiratory tract infections is included, with an emphasis on olfactory dysfunction.

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.

Oral Somatosensory Sensitivity in Patients With Taste Disturbance

OBJECTIVE

The significance of the human sense of taste is typically underestimated until it is altered or even lost. Hypogeusia, a diminished capacity to taste, has an adverse influence on a patient's quality of life. Similar to interactions between the oral senses and between olfaction and intranasal trigeminal sensitivity, taste disturbance may also affect the mechanosensitivity of the tongue. In this study, we investigated the lingual tactile sensitivity of patients with subjective taste disturbance and people with normogeusia.

STUDY DESIGN

Prospective case-control study.

METHODS

Forty-six patients with subjective taste disturbance (mean age 60 years) and 43 participants with normogeusia (mean age 55 years) were enrolled and underwent a stereognostic test of edge and point sensitivity based on 3D-printed letters sized from 2 to 8 mm. Gustatory function and salivary production were also tested.

RESULTS

Patients with dysgeusia needed significantly bigger letters to recognize them compared with controls (P = .01). Apart from this, patients with dysgeusia had no significant association between gustatory function and salivary production. Duration of dysgeusia and age were not associated with the presently obtained measures of gustatory or oral mechanosensory function.

CONCLUSIONS

The results of this study indicate that taste dysfunction has a negative impact on oral mechanosensitivity and hence possibly on oral texture perception.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:2572-2577, 2021.

Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

The year 2020 became the year of the outbreak of coronavirus, SARS-CoV-2, which escalated into a worldwide pandemic and continued into 2021. One of the unique symptoms of the SARS-CoV-2 disease, COVID-19, is the loss of chemical senses, i.e., smell and taste. Smell training is one of the methods used in facilitating recovery of the olfactory sense, and it uses essential oils of lemon, rose, clove, and eucalyptus. These essential oils were not selected based on their chemical constituents. Although scientific studies have shown that they improve recovery, there may be better combinations for facilitating recovery. Many phytochemicals have bioactive properties with anti-inflammatory and anti-viral effects. In this review, we describe the chemical compounds with anti- inflammatory and anti-viral effects, and we list the plants that contain these chemical compounds. We expand the review from terpenes to the less volatile flavonoids in order to propose a combination of essential oils and diets that can be used to develop a new taste training method, as there has been no taste training so far. Finally, we discuss the possible use of these in clinical settings.

ASSESSMENT OF OLFACTORY AND GUSTATORY FUNCTIONS IN COVID-19 PATIENTS

Background/aim

This study aims to evaluate of olfactory and gustatory functions of COVID-19 patients and possible risk factors for olfactory and gustatory dysfunctions.

Materials and methods

The cross-sectional study included adult patients who were diagnosed with COVID-19 in Gazi University Hospital between April 2020 and June 2020. Volunteered patients participated in a survey in which olfactory and gustatory functions and various clinical information were questioned. Sinonasal Outcome Test-22 was also administrated to all patients.

Results

A hundred and seventy-one patients participated in this study. Olfactory and gustatory dysfunctions rates were 10.5% (n: 18) and 10.5% (n: 18), respectively. Patients without any symptom other than smell and taste dysfunctions were clustered as group 1 and patients who are clinically symptomatic were clustered as group 2. Olfactory dysfunction occurred in 8% of group 1 and 17.4% of group 2 (p = 0.072). Gustatory dysfunction rate of smokers was 19.7% and significantly higher than gustatory dysfunction rate of nonsmokers (5.5%) (p = 0.007). Twenty-seven-point-eight percent of the patients with olfactory dysfunction (n = 5) were male and 72.2% (n: 13) were female. Sex did not show significant effect on rate of olfactory dysfunction. Twenty-five patients participated in psychophysical olfactory function test. No participant reported olfactory dysfunction at the time of test. Of the participants, 64% (n: 16) were normosmic and 36% (n: 9) were hyposmic according to Sniffin’ Stick test.

Conclusion

Olfactory and gustatory dysfunctions are more common in patients who are clinically symptomatic than those diagnosed during contact tracing. Objective tests may show that frequency of olfactory dysfunction is greater than frequency of self-reported olfactory dysfunction.

Gustatory dysfunction in COVID-19 patients: a rapid systematic review on 27,687 cases

Objective: This is a rapid systematic review concerning taste alterations in 27,687 individuals infected with SARS-CoV-2, published in the worldwide literature.Material and methods: Of the 485 articles recovered, 67 eligible studies (27,687 confirmed COVID-19 cases) were included in this analysis. We analysed the prevalence of the taste alterations in patients considering the country of origin of the studies.Results: The results show strong important differences in the overall reported prevalence of taste alterations among the different countries (from 11% of Korea to 88.8% of Belgium).Conclusions: These data highlight that there is a different geographical distribution of taste alterations in COVID-19 patients. Gustatory dysfunction seems to be an understudied symptom of COVID-19 and this may explain the inconsistencies of diagnostic criteria for COVID-19 case definition. Furthermore, this diagnostic underestimation can lead to an increased risk of contagion for the whole population and for the working classes most at risk, including the dental one.

Effect of concentrated growth factors on quality of life of patients undergoing implant therapy: a cohort study

Pain, bad taste, and impaired daily activity after implant therapy are common sequelae. Concentrated growth factors (CGF) are a platelet concentrate with a favourable effect on wound healing, but there is still no evidence regarding its potential benefits for reducing postoperative pain and symptoms. Therefore, aim of this prospective comparative study was to determine the effect of CGF on quality of life (QoL) of patients after implant therapy. Fifty-two consecutive patients with one missing mandibular molar were included in the study and alternatively assigned to two groups. Control group received standard implant treatment, and test group received CGF associated with implants. Standard periapical radiographs were taken before and after procedure. Post-operative care consisted of 0.2% chlorhexidine digluconate solution twice daily for 10 days. A QoL questionnaire (OHIP-14) for bad taste, pain and limitation in daily activities was filled and returned one week post-operatively. Daily pain was also assessed through Visual Analogue Scale (VAS) on a 1-100 scale. Parametric test (chi-square) was performed to compare the results of the questionnaire between the two groups using STATA statistical software. All patients correctly filled and returned the questionnaire. Significantly higher proportions of patients of test group reported no bad taste, pain, and limited activity, (24/26, 13/26, and 25/26, respectively) respect to control. Postoperative pain with VAS score was significantly lower in the test group on day 1, 2, and 3 as compared to control. CGF positively influenced QoL when associated with implant rehabilitation of mandibular molars, minimizing post-operative discomfort.

Anosmia but Not Ageusia as a COVID-19-Related Symptom among Cancer Patients-First Results from the PAPESCO-19 Cohort Study

Background: Cancer patients may fail to distinguish COVID-19 symptoms such as anosmia, dysgeusia/ageusia, anorexia, headache, and fatigue, which are frequent after cancer treatments. We aimed to identify symptoms associated with COVID-19 and to assess the strength of their association in cancer and cancer-free populations. Methods: The multicenter cohort study PAPESCO-19 included 878 cancer patients and 940 healthcare workers (HCWs). At baseline and quarterly thereafter, they reported the presence or absence of 13 COVID-19 symptoms observed over 3 months and the results of routine screening RT-PCR, and they were systematically tested for SARS-CoV-2-specific antibodies. We identified the symptom combinations significantly associated with COVID-19. Results: Eight percent of cancer patients were COVID-19 positive, and 32% were symptomatic. Among the HCWs, these proportions were 9.5 and 52%, respectively. Anosmia, anorexia, fever, headache, and rhinorrhea together accurately discriminated (c-statistic = 0.7027) COVID-19 cases from cancer patients. Anosmia, dysgeusia/ageusia, muscle pain, intense fatigue, headache, and chest pain better discriminated (c-statistic = 0.8830) COVID-19 cases among the HCWs. Anosmia had the strongest association in both the cancer patients (OR = 7.48, 95% CI: 2.96-18.89) and HCWs (OR = 5.71, 95% CI: 2.21-14.75). Conclusions: COVID-19 symptoms and their diagnostic performance differ in the cancer patients and HCWs. Anosmia is associated with COVID-19 in cancer patients, while dysgeusia/ageusia is not. Cancer patients deserve tailored preventive measures due to their particular COVID-19 symptom pattern.

Positive Long-Term Effects of Third Molar Extraction on Taste Function

Taste and other neurosensory defects have been reported postoperatively in a number of patients who have undergone mandibular third molar extraction (TME). Although the taste deficits are generally believed to resolve within a year, the long-term effects of TME remain unknown. We retrospectively examined the whole-mouth taste function of 891 individuals who had received TMEs, on average, more than 2 decades earlier, and 364 individuals who had not undergone TME. All had been extensively tested for chemosensory function at the University of Pennsylvania Smell and Taste Center over the course of the last 20 years. The whole-mouth identification test incorporated 2 presentations each of 5 different concentrations of sucrose, sodium chloride, citric acid, and caffeine. Analyses of covariance (age = covariate) found those with histories of TME to exhibit better overall test scores for all 4 taste qualities than nonoperated controls. Such scores were not associated with the time since the TME. In both groups, women outperformed men and function declined with age. The basis of this phenomenon, which requires confirmation from prospective studies, is unknown, but could reflect sensitization of CN VII nerve afferents or the partial release of the tonic inhibition that CN VII exerts on CN IX via central nervous system processes.

Clinical Presentation of Asymptomatic and Mild SARS-CoV-2 Infection in Riyadh, Saudi Arabia

Background

There is substantial evidence that most SARS-CoV-2 infections are mild or even asymptomatic, yet they can transmit the virus to others. The current study described the clinical presentation of mild COVID-19 cases isolated in the ministry of health (MOH) quarantines in Riyadh, Saudi Arabia.

Methods

A cross-sectional study targeted the SARS-CoV-2 PCR +ve asymptomatic and mild COVID-19 patients isolated in the Saudi MOH quarantines in Riyadh city between July and December 2020. The confirmed COVID-19 patients were enrolled and interviewed by telephones after obtaining the informed consent.

Results

The study included 223 patients with a mean age of 32.5±10.7 years old. The majority were male 156 (70%). Only 27 [12.1%; 95% CI = (8.1–17.1%)] were asymptomatic. General fatigue was the most common reported symptom, 43.5%, followed by headache with 42.6%, and cough by 38.1%. Anosmia and ageusia were reported by 33.2% and 31.4%, respectively. The least common reported symptoms were vomiting, earache, and nausea with 1.8%, 4.0%, and 7.6%, respectively.

Conclusion

The top five clinical manifestations of mild COVID-19 cases were general fatigue, headache, cough, anosmia, and ageusia. Only 12% of confirmed COVID-19 cases were asymptomatic.

Geographical Variations in Host Predisposition to COVID-19 Related Anosmia, Ageusia, and Neurological Syndromes

The novel coronavirus disease (COVID-19), has become the most critical global health challenge in recent history. With SARS-CoV-2 infection, there was an unexpectedly high and specific prevalence of olfactory and taste disorders (OTDs). These high rates of hyposmia and hypogeusia, initially reported as up to 89% in European case series, led to the global inclusion of loss of taste and/or smell as a distinctive feature of COVID-19. However, there is emerging evidence that there are striking differences in the rates of OTDs in East Asian countries where the disease first emerged, as compared to Western countries (15.8 vs. 60.9%, p-value < 0.01). This may be driven by either variations in SARS-CoV-2 subtypes presenting to different global populations or genotypic differences in hosts which alter the predisposition of these different populations to the neuroinvasiveness of SARS-CoV-2. We also found that rates of OTDs were significantly higher in objective testing for OTDs as compared to subjective testing (73.6 vs. 60.8%, p-value = 0.03), which is the methodology employed by most studies. Concurrently, it has also become evident that racial minorities across geographically disparate world populations suffer from disproportionately higher rates of COVID-19 infection and mortality. In this mini review, we aim to delineate and explore the varying rates of olfactory and taste disorders amongst COVID-19 patients, by focusing on their underlying geographical, testing, ethnic and socioeconomic differences. We examine the current literature for evidence of differences in the olfactory and gustatory manifestations of COVID-19 and discuss current pathophysiological hypotheses for such differences.

Loss of Smell and Taste in Patients With Suspected COVID-19: Analyses of Patients' Reports on Social Media

BACKGROUND

The year 2020 was the year of the global COVID-19 pandemic. The severity of the situation has become so substantial that many or even most of the patients with mild to moderate symptoms had to self-isolate without specific medical treatments or even without being tested for COVID-19. Many patients joined internet membership groups to exchange information and support each other.

OBJECTIVE

Our goal is to determine the benefits and limits of using social media to understand the symptoms of patients with suspected COVID-19 with mild to moderate symptoms and, in particular, their symptoms of anosmia (loss of the sense of smell) and ageusia (loss of the sense of taste). The voluntary reports on an internet website of a membership group will be the platform of the analyses.

METHODS

Posts and comments of members of an internet group known as COVID-19 Smell and Taste Loss, founded on March 24, 2020, to support patients with suspected COVID-19 were collected and analyzed daily. Demographic data were collected using the software mechanism called Group Insights on the membership group website.

RESULTS

Membership groups on social media have become rare sources of support for patients with suspected COVID-19 with mild to moderate symptoms. These groups provided mental support to their members and became resources for information on COVID-19 tests and medicines or supplements. However, the membership was voluntary, and often the members leave without notification. It is hard to be precise from the free voluntary reports. The number of women in the group (6995/9227, 75.38% as of October 12, 2020) was about three times more than men (2272/9227, 24.62% as of October 12, 2020), and the peak age of members was between 20-40 years in both men and women. Patients who were asymptomatic other than the senses comprised 14.93% (53/355) of the total patients. Recovery of the senses was higher in the patients who were asymptomatic besides having anosmia and ageusia. Most (112/123, 91.06%) patients experienced other symptoms first and then lost their senses, on average, 4.2 days later. Patients without other symptoms tended to recover earlier (P=.02). Patients with anosmia and ageusia occasionally reported distorted smell and taste (parosmia and dysgeusia) as well as experiencing or perceiving the smell and taste without the sources of the smell or taste (phantosmia and phantogeusia).

CONCLUSIONS

Our analysis of the social media database of suspected COVID-19 patients' voices demonstrated that, although accurate diagnosis of patients is not always obtained with social media-based analyses, it may be a useful tool to collect a large amount of data on symptoms and the clinical course of worldwide rapidly growing infectious diseases.

COVID-19-Induced Anosmia and Ageusia Are Associated With Younger Age and Lower Blood Eosinophil Counts

BACKGROUND

Anosmia and ageusia are symptoms commonly associated with COVID-19, but the relationship with disease severity, onset and recovery are unclear.

OBJECTIVE

To examine factors associated with anosmia and ageusia and the recovery from these symptoms in an ethnically diverse cohort.

METHODS

Individuals tested for SARS-CoV-2 between March and April 2020 were eligible for the study. Randomly selected participants answered a telephone questionnaire on COVID-19 symptoms with a focus on anosmia and ageusia. Additionally, relevant past medical history and data on the COVID-19 clinical course were obtained from electronic medical records. 486 patients were in the COVID-19 group and 103 were COVID-19-negative.

RESULTS

Patients who were younger were more likely to report anosmia and/or ageusia (odds ratio (OR) for anosmia per 1-year increase in age: 0·98, 95%CI:0-97-0·99, p = 0·003; for ageusia: 0·98, 95%CI:0·97-0·99, p = 0·005) as were patients with lower eosinophil counts (OR for anosmia per 0.1-K/μL increase in eosinophils: 0·02, 95%CI:0·001-0·46, p = 0·01, for ageusia 0·10, 95%CI:0·01-0·97, p = 0·047). Male gender was independently associated with a lower probability of ageusia (OR:0·56, 95%CI:0·38-0·82, p = 0·003) and earlier sense of taste recovery (HR:1·44, 95%CI:1·05-1·98, p = 0·02). Latinos showed earlier sense of taste recovery than white patients (HR:1·82, 95%CI:1·05-3·18, p = 0·03).

CONCLUSION

Anosmia and ageusia were more common among younger patients and those with lower blood eosinophil counts. Ageusia was less commonly reported among men, and time to taste recovery was earlier among both men and Latinos.