Recovery rate and factors associated with smell and taste disruption in patients with coronavirus disease 2019

Chemosensory function recovery in COVID-19 patients: A cross-sectional study

OBJECTIVE

To determine whether subjects who have recovered from COVID-19 smell and taste disturbance perform similarly to their COVID-naïve baseline, on gold-standard smell and taste tests.

STUDY DESIGN

Prospective cross-sectional study.

SETTING

University of Miami Department of Otolaryngology in Miami, FL between September 2021, and August 2022.

METHODS

Those previously COVID-19 positive composed the experimental group, those who reported being COVID-naïve composed the control group. Mean total score for the UPSIT Smell Test, and the Burghart Taste Strip test were the primary outcome measures.

RESULTS

70 adult subjects (35 former COVID-positive, 35 COVID-naïve) were enrolled, with 21 females and 14 males in each group. 87 % of all subjects were white and were almost distributed evenly between Hispanic and non-Hispanic. Mean UPSIT total score for the experimental group was 30.6 (95 % CI 28.9-32.3), mean UPSIT total score for the control group was 31.2 (95 % CI 29.7-32.8). Mean Burghart total score for the experimental group was 11.3 (95 % CI 10.6-12.0), mean Burghart total score for the control group was 10.7 (95 % CI 9.7-11.8). These showed a significant overlap of the 95 % CI of the mean total score between the control group and the experimental group, suggesting no significant difference between the two groups.

CONCLUSION

These results suggest that COVID-19 patients who experience smell and taste disturbance and recover, regain sensory ability similar to their pre-COVID ability. Further study is needed to validate these findings, but the results are promising in the long-term recovery of COVID-19.

One-year psychophysical evaluation of COVID-19-induced olfactory disorders: a prospective cohort study

BACKGROUND

Olfactory disorders are common in COVID-19. While many patients recover within weeks, a notable number of patients suffer from prolonged olfactory disorders. Much research has focused on the acute phase of olfactory disorders in COVID-19; however, there is still inconsistency regarding the prognosis. We aim to assess both objective and subjective olfactory function in patients with persisting olfactory disorders following COVID-19, 1 year after diagnosis.

METHODS

We objectively measured olfactory function in 77 patients who initially had COVID-19-induced smell disorders, 1 year after confirmed diagnosis. These patients previously underwent two objective measurements at approximately 3 and 6 months after COVID-19, in the context of the COCOS trial (COrticosteroids for COvid-19-induced loss of Smell). The main outcome measurement was TDI score (threshold-discrimination-identification) on Sniffin' Sticks Test (SST). Secondary outcomes included objective gustatory function on Taste Strip Test (TST), self-reported olfactory, gustatory and trigeminal function on a visual analogue scale (VAS) and outcomes on questionnaires about quality of life, and nasal symptoms.

RESULTS

The findings of this study show that 1 year following COVID-19, the median TDI score increased to 30.75 (IQR 27.38-33.5), regarded as normosmia. The median TDI score started at 21.25 (IQR 18.25-24.75) at baseline and increased to 27.5 (IQR 23.63-30.0) at 6 months following COVID-19. The increase of 9.5 points on the TDI score between baseline and 1 year after COVID-19 marks a clinically relevant improvement. Regarding the self-reported VAS score (1-10) on sense of smell, it increased from 1.2 (IQR 0.4-3.0) at baseline to 3.2 (IQR 1.4-6.0) at 6 months and further improved up to 6.1 (IQR 2.7-7.5) after 1 year. Objective gustatory function increased with 2 points on TST a year after diagnosis. Self-reported olfactory, gustatory, and trigeminal functions also improved over time, as did quality of life.

CONCLUSIONS

Objective and self-reported olfactory function continued to improve 1 year after COVID-19. The median TDI score of 30.75 (IQR 27.38-33.5) is regarded as normosmia, which is a favorable outcome. However, the rate of improvement on TDI score reduces over time.

Olfactory dysfunction among patients with COVID-19

OBJECTIVES

To assess the frequency of olfactory dysfunction (OD) among individuals afflicted with coronavirus disease of 2019 (COVID-19).

METHODS

A comprehensive literature search was carried out across several bibliographical databases (PubMed, Scopus, Google Scholar, and Web of Science) to extract publications in the English language between January 2020 and December 2021 to report the incidence of OD alone or together with gustatory dysfunction (GD) among COVID-19 patients.

RESULTS

Based on eligibility criteria, 84 articles were included from 27 countries, comprising 36,903 patients, of whom 58.1% were females. The generality rates of olfactory impairment alone was 34.60% and in conjunction with GD was 11.36%. Patients with OD were subclassified into various categories, and the prevalence of anosmia was 20.85%, 5.04% for hyposmia, 8.88% for anosmia or hyposmia, 1.84% for parosmia, 0.78% for phantosmia, and 0.02% for hyperosmia, among COVID-19 patients.

CONCLUSION

Clinical features associated with OD, either isolated or in combination with GD, are common in patients with COVID-19 and consider important signs of COVID-19 that may guide clinicians in the early phase of the disease.PROSPERO Reg. No.: 417296.

Erectile dysfunction after COVID-19 recovery: A follow-up study

Objectives

Several studies confirm multiple complications after COVID-19 infection, including men’s sexual health, which is caused by both physical and psychological factors. However, studies focusing on long-term effects among recovered patients are still lacking. Therefore, we aimed to investigate the erectile function at three months after COVID-19 recovery along with its predicting factors.

Methods

We enrolled all COVID-19 male patients, who were hospitalized from May to July 2021, and declared to be sexually active within the previous two weeks. Demographic data, mental health status, and erectile function were collected at baseline and prospectively recollected three months after hospital discharge. To determine changes between baseline and the follow-up, a generalized linear mixed effect model (GLMM) was used. Also, logistic regression analysis was used to identify the associating factors of erectile dysfunction (ED) at three months.

Results

One hundred fifty-three men with COVID-19 participated. Using GLMM, ED prevalence at three months after recovery was 50.3%, which was significantly lower compared with ED prevalence at baseline (64.7%, P = 0.002). Declination of prevalence of major depression and anxiety disorder was found, but only major depression reached statistical significance (major depression 13.7% vs. 1.4%, P < 0.001, anxiety disorder 5.2% vs. 2.8% P = 0.22). Logistic regression, adjusted for BMI, medical comorbidities, and self-reported normal morning erection, showed a significant association between ED at three months and age above 40 years and diagnosis of major depression with adjusted OR of 2.65, 95% CI 1.17–6.01, P = 0.02 and 8.93, 95% CI 2.28–34.9, P = 0.002, respectively.

Conclusion

Our study showed a high ED prevalence during the third month of recovery from COVID-19. The predicting factors of persistent ED were age over 40 years and diagnosis of major depression during acute infection.

Persistence of COVID-19 symptoms beyond 3 months and the delayed return to the usual state of health in Saudi Arabia: A cross-sectional study

A substantial number of COVID-19 survivors describe ongoing symptoms long after the acute phase. This so-called post-COVID-19 syndrome or long COVID occurs irrespective of initial disease severity.

Recovery from Covid-19 smell loss: Two-years of follow up

Objective

To report long-term patterns of recovery and non-recovery in a large nationwide cohort of subjects with COVID-19 associated smell loss.

Study design

Prospectively, longitudinal questionnaires.

Setting

Web-based national survey.

Methods

A longitudinal survey of adults with COVID-19 and/or sudden change in smell or taste since January 1, 2020 was launched April 10, 2020. Participants were queried again in late May 2022 regarding recovery. Data from respondents with >2 years since loss were analyzed and compared to recovery status of those more recently effected.

Results

1103 responded to the survey of whom 946 met inclusion criteria. Among the 267 respondents for whom at least 2 years of follow up was available, 38.2 % reported full recovery, 54.3 % partial, and 7.5 % no recovery. For the entire cohort (all with ≥3 months since smell loss), 38.7 % reported complete recovery, 51.0 % reported partial recovery (ranging from mild complaints to severe phantosmia or dysosmia), and 10.3 % reported no improvement at all. Complete recovery of smell function was significantly higher in those under 40 years old (45.6 % compared to 32.9 % in those over 40).

Conclusion

Although the vast majority of subjects who do recover do so within the first 3 months, long-term spontaneous recovery can occur. Rates of recovery do not seem to differ depending on when during the pandemic the loss first occurred.

Searching for Factors Influencing the Severity of the Symptoms of Long COVID

COVID-19 is a highly contagious respiratory disease. Infection with the virus can occur with differing symptom severity, from mild and moderate to severe cases, but the long-term consequences of infection have not been fully identified or studied. Long COVID is defined as occurring in individuals with a history of probable or confirmed SARS-CoV-2 infection, and symptoms persisting for at least two months within three months of onset that cannot be explained by an alternative diagnosis. The purpose of this study was to look for factors that influence the type and severity of Long COVID symptoms. In total, 932 individuals with a history of COVID-19 were qualified for the study using an original questionnaire based on the COVID-19 Yorkshire Rehab Screen (C19-YRS) questionnaire. Older adults were more likely to report problems with mobility (p < 0.001) and in performing daily activities (p = 0.014). Those with a higher BMI showed significantly more symptoms such as dyspnea at rest (p < 0.001) and on exertion (p < 0.001), feelings of chronic fatigue (p = 0.023), problems with mobility (p < 0.001), and in performing daily activities (p = 0.002). The data show that those with Long COVID should receive multidisciplinary help including additional medical and psychological support. Particular attention should be paid to elderly and obese persons, who should be included in rehabilitation programs after COVID-19 in the first place.

The Prevalence and Implications of Olfactory/Gustatory Dysfunctions among Adult COVID-19 Patients: A Retrospective Cohort Multiethnic Populations Study

(1) Background: Olfactory and gustatory dysfunctions (OGDs) was found in COVID-19 patients. Only a few studies looked into the prevalence of OGDs in the United Arab Emirates (UAE). The purpose of this study was to estimate the prevalence OGDs among multiethnic COVID-19 patients in the UAE, and its association to patients’ characteristics and disease outcomes; (2) Methods: There were 1785 COVID-19 patients included in our cohort; (3) Results: Males made up most of the study participants (86.3%). A total of 11.7% of the participants reported OGDs. Female gender and ethnicity had significantly higher symptom prevalence (p < 0.001). COVID-19 severity had a strong inverse association with OGDs (p = 0.007). Other illness outcomes, such as ICU admission, pneumonia development, and mortality, showed no correlation. Males, Asians, and patients with comorbidities all had statistically significantly lower prevalence odds. On the other hand, Emirati, Arab, and Iranian patients had a higher prevalence. COVID-19 patients with OGDs had a considerably shorter time until viral clearance than those without the symptom; (4) Conclusions: in nonsevere COVID-19, olfactory/gustatory dysfunction is common. As a result, it could be applied as a predictive sign for early disease diagnosis and prognosis.

Prevalence of post-acute COVID-19 syndrome symptoms at different follow-up periods: a systematic review and meta-analysis

BACKGROUND

Post-acute coronavirus 2019 (COVID-19) syndrome is now recognized as a complex systemic disease that is associated with substantial morbidity.

OBJECTIVES

To estimate the prevalence of persistent symptoms and signs at least 12 weeks after acute COVID-19 at different follow-up periods.

DATA SOURCES

Searches were conducted up to October 2021 in Ovid Embase, Ovid Medline, and PubMed.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Articles in English that reported the prevalence of persistent symptoms among individuals with confirmed severe acute respiratory syndrome coronavirus 2 infection and included at least 50 patients with a follow-up of at least 12 weeks after acute illness.

METHODS

Random-effect meta-analysis was performed to produce a pooled prevalence for each symptom at four different follow-up time intervals. Between-study heterogeneity was evaluated using the I2 statistic and was explored via meta-regression, considering several a priori study-level variables. Risk of bias was assessed using the Joanna Briggs Institute tool and the Newcastle-Ottawa Scale for prevalence studies and comparative studies, respectively.

RESULTS

After screening 3209 studies, a total of 63 studies were eligible, with a total COVID-19 population of 257 348. The most commonly reported symptoms were fatigue, dyspnea, sleep disorder, and difficulty concentrating (32%, 25%, 24%, and 22%, respectively, at 3- to <6-month follow-up); effort intolerance, fatigue, sleep disorder, and dyspnea (45%, 36%, 29%, and 25%, respectively, at 6- to <9-month follow-up); fatigue (37%) and dyspnea (21%) at 9 to <12 months; and fatigue, dyspnea, sleep disorder, and myalgia (41%, 31%, 30%, and 22%, respectively, at >12-month follow-up). There was substantial between-study heterogeneity for all reported symptom prevalences. Meta-regressions identified statistically significant effect modifiers: world region, male sex, diabetes mellitus, disease severity, and overall study quality score. Five of six studies including a comparator group consisting of COVID-19-negative cases observed significant adjusted associations between COVID-19 and several long-term symptoms.

CONCLUSIONS

This systematic review found that a large proportion of patients experience post-acute COVID-19 syndrome 3 to 12 months after recovery from the acute phase of COVID-19. However, available studies of post-acute COVID-19 syndrome are highly heterogeneous. Future studies need to have appropriate comparator groups, standardized symptom definitions and measurements, and longer follow-up.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Gustatory Function in Acute COVID ‐19 ‐ Results from Home‐Based Psychophysical Testing

Objective

Gustatory function during COVID‐19 is self‐reported by around 50% of patients. However, only a few studies assessed gustation using psychophysical testing during acute infection. The objective of this study is to test gustatory function on threshold tests in the very first days of COVID‐19.

Methods

Psychophysical testing consisted of validated and blinded tests for olfaction (NHANES Pocket Smell Test) and gustation (Taste Strips Test). These test kits were sent to home‐quarantined patients and self‐administered using a detailed instruction sheet.

Results

A total of 51 patients were included in this study. Testing was performed 6.5 ± 2.7 days after sampling of respiratory swabs. At this time 37% of patients stated to currently experience a gustatory impairment. The mean Taste Strips score was 10.0 ± 3.4 with 28% scoring in the range of hypogeusia. Interestingly, no significant difference in the results of gustatory testing could be observed between the group with subjectively preserved gustation and the group with self‐rated taste impairment.

Conclusion

During the very first days of COVID‐19, psychophysical gustatory testing revealed hypogeusia in 28%. This is far lower than patients' self‐reports. Different from previous studies, we did not find clear evidence for an impairment of only certain taste qualities.

Level of Evidence

3 Laryngoscope, 132:1082–1087, 2022

Post-COVID-19 Syndrome: Involvement and Interactions between Respiratory, Cardiovascular and Nervous Systems

Though the acute effects of SARS-CoV-2 infection have been extensively reported, the long-term effects are less well described. Specifically, while clinicians endure to battle COVID-19, we also need to develop broad strategies to manage post-COVID-19 symptoms and encourage those affected to seek suitable care. This review addresses the possible involvement of the lung, heart and brain in post-viral syndromes and describes suggested management of post-COVID-19 syndrome. Post-COVID-19 respiratory manifestations comprise coughing and shortness of breath. Furthermore, arrhythmias, palpitations, hypotension, increased heart rate, venous thromboembolic diseases, myocarditis and acute heart failure are usual cardiovascular events. Among neurological manifestations, headache, peripheral neuropathy symptoms, memory issues, lack of concentration and sleep disorders are most commonly observed with varying frequencies. Finally, mental health issues affecting mental abilities and mood fluctuations, namely anxiety and depression, are frequently seen. Finally, long COVID is a complex syndrome with protracted heterogeneous symptoms, and patients who experience post-COVID-19 sequelae require personalized treatment as well as ongoing support.

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.

The prior infection with SARS-CoV-2 study (PICOV) in nursing home residents and staff - study protocol description and presentation of preliminary findings on symptoms

Background

The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has presented itself as one of the most important health concerns of the 2020’s, and hit the geriatric population the hardest. The presence of co-morbidities and immune ageing in the elderly lead to an increased susceptibility to COVID-19, as is the case for other influenza-like illnesses (ILI) or acute respiratory tract infections (ARI). However, little is known, about the impact of a previous or current infection on the other in terms of susceptibility, immune response, and clinical course. The aim of the “Prior Infection with SARS-COV-2” (PICOV) study is to compare the time to occurrence of an ILI or ARI between participants with a confirmed past SARS-CoV-2 infection (previously infected) and those without a confirmed past infection (naïve) in residents and staff members of nursing homes. This paper describes the study design and population characteristics at baseline.

Methods

In 26 Belgian nursing homes, all eligible residents and staff members were invited to participate, resulting in 1,226 participants. They were classified as naïve or previously infected based on the presence of detectable SARS-CoV-2 antibodies and/or a positive RT-qPCR result before participation in the study. Symptoms from a prior SARS-CoV-2 infection between March and August 2020 were compared between previously infected residents and staff members.

Results

Infection naïve nursing home residents reported fewer symptoms than previously infected residents: on average 1.9 and 3.1 symptoms, respectively (p = 0.016). The same effect was observed for infection naïve staff members and previously infected staff members (3.1 and 6.1 symptoms, respectively; p <0.0001). Moreover, the antibody development after a SARS-CoV-2 infection differs between residents and staff members, as previously infected residents tend to have a higher rate of asymptomatic cases compared to previously infected staff members (20.5% compared to 12.4%; p <0.0001).

Conclusions

We can postulate that COVID-19 disease development and symptomatology are different between a geriatric and younger population. Therefore, the occurrence and severity of a future ILI and/or ARI might vary from resident to staff.

Mechanism of Anosmia Caused by Symptoms of COVID-19 and Emerging Treatments

The occurrence of anosmia, the loss or change in sense of smell, is one of the most common symptoms of COVID-19 experienced by almost 53% of those affected. Several hypotheses explain the mechanism of anosmia in patients suffering from COVID-19. This study aims to review the related mechanisms and answer the questions regarding COVID-19-related anosmia as well as propose a new strategy for treatment of long-term anosmia as a result of COVID-19 infection. This paper covers all of the studies investigating olfactory disorders following COVID-19 infection and explains the possible reasons for the correlated anosmia, including olfactory cleft syndrome, local inflammation in the nasal epithelium, early apoptosis of olfactory cells, changes in olfactory cilia and odor transmission, damage to microglial cells, effect on olfactory bulbs, epithelial olfactory injury, and impairment of olfactory neurons and stem cells. The key questions that arise in this field have been discussed, such as why prevalent anosmia is varied among the age categories and among sexes and the correlation of anosmia with mild or severe COVID-19 infection. The angiotensin-converting enzyme 2 receptor is a significant player in the mechanism of anosmia in COVID-19 patients. Based on current studies, a novel approach to treat long-COVID-19 with ongoing anosmia has been proposed. The fields of smart drug delivery, tissue engineering, and cell therapy provide a hypothesized strategy that can minimize the side effects of current treatments and support efficient recovery of the olfactory system.

Characterising long COVID: a living systematic review

BACKGROUND

While it is now apparent clinical sequelae (long COVID) may persist after acute COVID-19, their nature, frequency and aetiology are poorly characterised. This study aims to regularly synthesise evidence on long COVID characteristics, to help inform clinical management, rehabilitation strategies and interventional studies to improve long-term outcomes.

METHODS

A living systematic review. Medline, CINAHL (EBSCO), Global Health (Ovid), WHO Global Research on COVID-19 database, LitCovid and Google Scholar were searched till 17 March 2021. Studies including at least 100 people with confirmed or clinically suspected COVID-19 at 12 weeks or more post onset were included. Risk of bias was assessed using the tool produced by Hoy et al. Results were analysed using descriptive statistics and meta-analyses to estimate prevalence.

RESULTS

A total of 39 studies were included: 32 cohort, 6 cross-sectional and 1 case-control. Most showed high or moderate risk of bias. None were set in low-income countries and few included children. Studies reported on 10 951 people (48% female) in 12 countries. Most included previously hospitalised people (78%, 8520/10 951). The longest mean follow-up time was 221.7 (SD: 10.9) days post COVID-19 onset. Over 60 physical and psychological signs and symptoms with wide prevalence were reported, most commonly weakness (41%; 95% CI 25% to 59%), general malaise (33%; 95% CI 15% to 57%), fatigue (31%; 95% CI 24% to 39%), concentration impairment (26%; 95% CI 21% to 32%) and breathlessness (25%; 95% CI 18% to 34%). 37% (95% CI 18% to 60%) of patients reported reduced quality of life; 26% (10/39) of studies presented evidence of reduced pulmonary function.

CONCLUSION

Long COVID is a complex condition with prolonged heterogeneous symptoms. The nature of studies precludes a precise case definition or risk evaluation. There is an urgent need for prospective, robust, standardised, controlled studies into aetiology, risk factors and biomarkers to characterise long COVID in different at-risk populations and settings.

PROSPERO REGISTRATION NUMBER

CRD42020211131.

Evolution of olfactory and gustatory dysfunctions in COVID-19 patients in India

PURPOSE

The ongoing coronavirus disease 19 (COVID-19) pandemic is spreading at an alarming rate across the globe. Sudden onset loss of smell and/or taste has been increasingly reported as a symptom of COVID-19. However, prevalence of these symptoms, and its severity varies widely between studies, with little data on its duration and recovery rate. Since this significantly impacts the quality of life of patients, there is a need for a study to provide insight into the loss of smell or taste in terms of its correlation with other upper respiratory tract symptoms, natural history and resolution rates.

METHODS

This cross-sectional study included 718 mild to moderately symptomatic adult patients (≥ 18 years), admitted consecutively to Kalinga Institute of Medical Sciences (KIMS), Odisha, India between June 25 and July 24, 2020, who tested positive for SARS-CoV-2 by polymerase chain reaction on nasopharyngeal and throat swabs. Prevalence, severity, duration and factors associated with altered smell or taste sensation, and their follow-up were recorded.

RESULTS

Of the 718 patients included in the study at baseline [563 (78%) men; median age 34 years], 101 (14%) patients experienced either altered smell or taste, with 52 (7%) experiencing both altered smell and taste. Seventy-seven (10.7%) patients had altered smell and 76 patients had altered taste (10.5%). Of these, 71 (92%) and 73 (96%) regained their sense of smell and taste, respectively, by 14 days after their swab tested positive. Presence of fever (OR = 5.4, 95% CI = 2.7-10.6, p < 0.001), cough (OR = 2.3, 95% CI = 1.2-4.2, p = 0.009) and nasal obstruction (OR = 3.1, 95% CI = 1.4-6.7, p = 0.006) were independently associated with increased likelihood of experiencing both altered taste and smell in multivariable models.

CONCLUSION

The prevalence of altered smell and taste in Indians was much lower compared to Europeans and similar to East Asians. Majority regained these senses by 2 weeks. Identification of these symptoms can help in early detection of the disease in suspected individuals.

Predictive factors of smell recovery in a clinical series of 288 coronavirus disease 2019 patients with olfactory dysfunction

BACKGROUND AND PURPOSE

The aim was to evaluate potential predictive factors of smell recovery in a clinical series of 288 patients presenting olfactory dysfunction (OD) related to coronavirus disease 2019 (COVID-19). Potential correlations were sought between epidemiological, clinical and immunological characteristics of patients and the persistence of OD at 60 days.

METHODS

COVID-19 positive patients presenting OD were prospectively recruited from three European hospitals. Baseline clinical and olfactory evaluations were performed within the first 2 weeks after OD onset and repeated at 30 and 60 days. In a subgroup of patients, anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies were measured in serum, saliva and nasal secretions at 60 days.

RESULTS

A total of 288 COVID-19 patients with OD were included in the study. Two weeks after the onset of the loss of smell, 52.4% of patients had OD on psychophysical tests, including 113 cases (39.2%) of anosmia and 38 cases (13.2%) of hyposmia. At 60-day follow-up, 25.4% of the patients presented persistent OD. There was no significant correlation between sex, age, viral load on nasopharyngeal swab or COVID-19 severity and poor olfactory outcome. In a subgroup of 63 patients, it was demonstrated that patients with poor olfactory outcomes at 60 days had lower levels of salivary and nasal immunoglobulin G (IgG) and IgG1, but similar levels of antibodies in the serum.

CONCLUSIONS

No clinical markers predicted the evolution of OD at 60 days. Patients with poor olfactory outcome at 60 days had lower saliva and nasal antibodies, suggesting a role for local immune responses in the persistence of COVID-19 related OD.

The outcome of olfactory impairment in patients with otherwise paucisymptomatic coronavirus disease 2019 during the pandemic

OBJECTIVE

This study aimed to measure the duration and recovery rate of olfactory loss in patients complaining of recent smell loss as their prominent symptom during the coronavirus disease 2019 outbreak.

METHOD

This was a prospective telephone follow-up observational study of 243 participants who completed an online survey that started on 12 March 2020.

RESULTS

After a mean of 5.5 months from the loss of smell onset, 98.3 per cent of participants reported improvement with a 71.2 per cent complete recovery rate after a median of 21 days. The chance of complete recovery significantly decreased after 131 days from the onset of loss of smell (100 per cent sensitive and 97.7 per cent specific). Younger age and isolated smell loss were associated with a rapid recovery, whereas accompanying rhinological and gastrointestinal symptoms were associated with longer loss of smell duration.

CONCLUSION

Smell loss, occurring as a prominent symptom during the coronavirus disease 2019 pandemic, showed a favourable outcome. However, after 5.5 months from the onset, around 10 per cent of participants still complained of moderate or severe hyposmia.

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

OBJECTIVES/HYPOTHESIS

Olfactory dysfunction has been observed as one of the clinical manifestations in COVID-19 patients. We aimed to conduct a systematic review and meta-analysis to estimate the overall pooled prevalence of olfactory dysfunction in COVID-19 patients.

STUDY DESIGN

Systematic review and meta-analyses.

METHODS

PubMed, Scopus, Web of Science, Embase, and Google Scholar databases were searched to identify studies published between 1 December 2019 and 23 July 2020. We used random-effects model to estimate the pooled prevalence with 95% confidence intervals (CIs). Heterogeneity was assessed using the I2 statistic and Cochran's Q test. Robustness of the pooled estimates was checked by different subgroup and sensitivity analyses This study is registered with PROSPERO (CRD42020183768).

RESULTS

We identified 1162 studies, of which 83 studies (n = 27492, 61.4% female) were included in the meta-analysis. Overall, the pooled prevalence of olfactory dysfunction in COVID-19 patients was 47.85% [95% CI: 41.20-54.50]. We observed olfactory dysfunction in 54.40% European, 51.11% North American, 31.39% Asian, and 10.71% Australian COVID-19 patients. Anosmia, hyposmia, and dysosmia were observed in 35.39%, 36.15%, and 2.53% of the patients, respectively. There were discrepancies in the results of studies with objective (higher prevalence) versus subjective (lower prevalence) evaluations. The discrepancy might be due to false-negative reporting observed in self-reported health measures.

CONCLUSIONS

The prevalence of olfactory dysfunction in COVID-19 patients was found to be 47.85% based on high-quality evidence. Due to the subjective measures of most studies pooled in the analysis, further studies with objective measures are advocated to confirm the finding.

LEVEL OF EVIDENCE

2 Laryngoscope, 131:865-878, 2021.

The Association of "Loss of Smell" to COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

The presence of olfactory dysfunction or "loss of smell" has been reported as an atypical symptom in patients with coronavirus disease 2019 (COVID-19). We performed a systematic review and meta-analysis of the available literature to evaluate the prevalence of "loss of smell" in COVID-19 as well as its utility for prognosticating the disease severity.

METHODS

An exhaustive search of the PubMed/Medline, Embase, Web of Science, Cochrane Library, LitCovid NIH, and WHO COVID-19 database was conducted through August 6th, 2020. All studies reporting the prevalence of "loss of smell" (anosmia and/or hyposmia/microsmia) in laboratory-confirmed COVID-19 patients were included. Pooled prevalence for cases (positive COVID-19 through reverse transcriptase (RT-PCR) and/or serology IgG/IgM) and controls (negative RT-PCR and/or serology) was compared, and the odds ratio (OR), 95% confidence interval (CI) and the p-value were calculated. A p-value of <0.05 was considered statistically significant.

RESULTS

A total of 51 studies with 11074 confirmed COVID-19 patients were included. Of these, 21 studies used a control group with 3425 patients. The symptom of "loss of smell" (OR: 14.7, CI: 8.9-24.3) was significantly higher in the COVID-19 group when compared to the control group. Seven studies comparing severe COVID-19 patients with- and without "loss of smell" demonstrated favorable prognosis for patients with "loss of smell" (OR: 0.36, CI 0.27-0.48).

CONCLUSIONS

Olfactory dysfunction or "loss of smell" is a prevalent symptom in COVID-19 patients. Moreover, COVID-19 patients with "loss of smell" appear to have a milder course of the disease.