Prevalence and 24-month recovery of olfactory dysfunction in COVID-19 patients: A multicentre prospective study.

OBJECTIVE: To investigate the prevalence and recovery of olfactory dysfunction (OD) in COVID-19 patients 24 months after the infection. METHODS: From 22 March 2020 to 5 June 2022, 251 COVID-19 patients were followed in three European medical centres. Olfactory function was assessed with subjective patient-reported outcome questionnaires and odour identification tests at baseline, 6, 12, 18 and 24 months postinfection. The predictive values of epidemiological and clinical data were investigated with multivariate analysis. RESULTS: One hundred and seventy-one patients completed the evaluations. The odour identification test revealed that 123 patients (50.8%) had OD at baseline. The prevalence of persistent psychophysical abnormalities at 6, 12, 18 and 24 months post-COVID-19 was 24.2%, 17.9%, 5.8% and 2.9%, respectively (p = 0.001). Parosmia occurred in 40 patients (23.4%) and lasted 60 ± 119 days. At 2 years, 51 patients (29.8%) self reported that their olfaction was unnormalised. Older patients had better odour identification evaluations at baseline (p < 0.001) but those with OD reported lower odour identification test scores at the end of the follow-up. Parosmia occurred more frequently in young patients. The olfactory training was significantly associated with higher values of Sniffin' Sticks tests at 18 months postinfection (rs = 0.678; p < 0.001). CONCLUSION: Two years post-COVID-19, 29.8% of patients reported persistent OD, but only 2.9% had abnormal identification psychophysical evaluations.

Comparison of prevalence and evolution of COVID-19 olfactory disorders in patients infected by D614 (wild) and B.1.1.7. Alpha variant: a brief report.

OBJECTIVES: To investigate the prevalence and the evolution of olfactory disorders (OD) related to coronavirus disease 2019 (COVID-19) in patients infected during the first and the second European waves. METHODS: From March 2020 to October 2020, COVID-19 patients with OD were recruited and followed over the 12-month post-infection. The following data were collected: demographic, treatments, vaccination status, and olfactory function. Olfaction was assessed with the Olfactory Disorder Questionnaire (ODQ), and threshold, discrimination, and identification (TDI) test. Outcomes were compared between patients of the first wave (group 1: wild/D614G virus) and the second wave (group 2: B.1.1.7. Alpha variant) at 1-, 3- and 12-month post-infection. RESULTS: Sixty patients completed the evaluations accounting for 33 and 27 patients in group 1 and 2, respectively. The 1-month TDI score (23.7 ± 5.3) was significantly lower in group 2 compared to group 1 (29.8 ± 8.7; p = 0.017). Proportion of normosmic patients at 1-month post-infection was significantly higher in group 1 compared to group 2 (p = 0.009). TDI scores only significantly increased from 1- to 3-month post-infection in anosmic and hyposmic patients. Focusing on There was a negative association between the 1-month ODQ and the 1-month TDI (rs = - 0.493; p = 0.012). ODQ was a significant predictor of TDI scores at 3- and 12-month post-infection. The 12-month prevalence of parosmia was 60.6% in group 1 and 42.4% in group 2, respectively. There was no significant influence of oral corticosteroid treatment, adherence to an olfactory training and vaccination status on the olfactory outcomes. CONCLUSIONS: Patients of the second wave (Alpha B.1.1.7. variant) reported significant higher proportion of psychophysical test abnormalities at 1-month post-infection than patients infected during the first wave (D614G virus).

Effectiveness of olfactory training in COVID-19 patients with olfactory dysfunction: a prospective study.

OBJECTIVES: To investigate effectiveness of olfactory training (OT) in COVID-19 patients with persistent olfactory dysfunction (OD). METHODS: From March 2020 to March 2022, COVID-19 patients with OD were prospectively followed in three European medical centers for a period of 18 months. A standardized OT protocol were recommended to patients. Patient-reported outcome questionnaires and psychophysical evaluations were used to evaluate olfaction at baseline, 6, 12, and 18 months after the start of OT. The evolution of olfactory outcome was compared according to the adherence to the OT protocol. RESULTS: Fifty-seven patients completed the evaluations. Thirty-two patients fully adhered to the OT, while 25 did not adhere. The psychophysical scores significantly improved from baseline to 6-month post-infection in both groups. In the OT group, the psychophysical scores continued to significantly improve from 6 to 12 months after the start of OT (p = 0.032). The mean duration of OT was 15.4 weeks. The mean delay of patient recovery perception was comparable between groups (27.4 weeks). The occurrence of cacosmia (35.1%) and parosmia (43.9%) throughout the follow-up period was comparable between groups. There proportion of phantosmia was higher in training (34.4%) compared with no-OT (16.0%; p = 0.007) group. The baseline Sniffin'Sticks tests was positively associated with the 6-month Sniffin'Sticks tests (rs = 0.685; p < 0.001) and negatively associated with the time of recovery (rs = - 0.369; p = 0.034). CONCLUSIONS: The adherence to an OT protocol was associated with better mid-term improvement of psychophysical scores. Future large-cohort randomized-controlled studies are needed to confirm the effectiveness of OT in COVID-19 patients.

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. LEVEL OF EVIDENCE: 4 Laryngoscope, 132:419-421, 2022.

COVID-19: Post-vaccine Smell and Taste Disorders: Report of 6 Cases.

Post-vaccine olfactory and gustatory disorders are very rare and were reported in patients who received influenza vaccines. In this article, we report 6 cases of post-coronavirus disease 2019 (COVID-19) vaccine olfactory and gustatory disorders in patients with negative nasal swabs. Precisely, olfactory and gustatory dysfunctions were reported in 5 and 1 patients, respectively. Sense disorders occurred after the first injection of AstraZeneca (n = 4) or the second injection of Pfizer (n = 2) vaccines. In 4 cases, the olfactory or gustatory disorder was confirmed with psychophysical evaluations. The duration of chemosensory dysfunction ranged from 4 to 42 days. None of the patient reported mid- or long-term olfactory or gustatory disorder. The occurrence of olfactory and gustatory dysfunctions in adults benefiting from COVID-19 vaccines is still rare but has to be known by otolaryngologists.

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.

Validity and reliability of the COVID-19 symptom index, an instrument evaluating severity of general and otolaryngological symptoms.

BACKGROUND: There is no clinical instrument evaluating symptoms of COVID-19. OBJECTIVE: To develop a clinical instrument for evaluating symptoms of COVID-19 mild-to-moderate forms. METHODS: COVID-19 patients were recruited from EpiCURA Hospital (Belgium). They completed the COVID-19 Symptom Index (CSI) twice to assess the test-retest reliability. The internal consistency was evaluated with Cronbach's alpha. CSI was completed by healthy subjects to assess the internal validity. Patients completed CSI 6 weeks after the COVID-19 resolution to evaluate the responsiveness to change. RESULTS: Ninety-four COVID-19 patients and 55 healthy individuals completed the evaluations. Symptoms associated with the higher severity score were fatigue, headache and myalgia. The Cronbach's alpha value was 0.801, indicating high internal consistency. The test-retest reliability was adequate (rs = 0.535, p = .001). The correlation between CSI total score and SNOT-22 was high (rs = 0.782; p < .001), supporting a high external validity. COVID-19 patients reported significant higher CSI score than healthy individuals, suggesting an adequate internal validity. The mean CSI significantly decreased after the COVID-19 resolution, supporting a high responsiveness to change property. CONCLUSION AND SIGNIFICANCE: The CSI is a reliable and valid patient reported outcome questionnaire for the evaluation of symptom severity of COVID-19 patients.

Epidemiological, otolaryngological, olfactory and gustatory outcomes according to the severity of COVID-19: a study of 2579 patients.

OBJECTIVE: To investigate prevalence and epidemiological and clinical factors associated with olfactory dysfunction (OD) and gustatory dysfunction (GD) in COVID-19 patients according to the disease severity. STUDY DESIGN: Cross-sectional study. METHODS: A total of 2579 patients with a positive diagnosis of COVID-19 were identified between March 22 and June 3, 2020 from 18 European hospitals. Epidemiological and clinical data were extracted. Otolaryngological symptoms, including OD and GD, were collected through patient-reported outcome questionnaire and Sniffin'Sticks tests were carried out in a subset of patients. RESULTS: A total of 2579 patients were included, including 2166 mild (84.0%), 144 moderate (5.6%) and 269 severe-to-critical (10.4%) patients. Mild patients presented an otolaryngological picture of the disease with OD, GD, nasal obstruction, rhinorrhea and sore throat as the most prevalent symptoms. The prevalence of subjective OD and GD was 73.7 and 46.8%, and decreases with the severity of the disease. Females had higher prevalence of subjective OD and GD compared with males. Diabetes was associated with a higher risk to develop GD. Among the subset of patients who benefited from psychophysical olfactory evaluations, there were 75 anosmic, 43 hyposmic and 113 normosmic patients. The prevalence of anosmia significantly decreased with the severity of the disease. Anosmia or hyposmia were not associated with any nasal disorder, according to SNOT-22. CONCLUSION: OD and GD are more prevalent in patients with mild COVID-19 compared with individuals with moderate, severe or critical diseases. Females might have a higher risk of developing OD and GD compared with males.

Severity of Anosmia as an Early Symptom of COVID-19 Infection May Predict Lasting Loss of Smell.

Introduction: To evaluate the recovery rate of loss of smell (LOS) with objective olfactory testing in COVID-19 patients. Methods: Adults with confirmed COVID-19 and self-reported sudden LOS were prospectively recruited through a public call from the University of Mons (Belgium). Epidemiological and clinical data were collected using online patient-reported outcome questionnaires. Patients benefited from objective olfactory evaluation (Sniffin-Sticks-test) and were invited to attend for repeated evaluation until scores returned to normal levels. Results: From March 22 to May 22, 2020, 88 patients with sudden-onset LOS completed the evaluations. LOS developed after general symptoms in 44.6% of cases. Regarding objective evaluation, 22 patients (25.0%) recovered olfaction within 14 days following the onset of LOS. The smell function recovered between the 16th and the 70th day post-LOS in 48 patients (54.5%). At the time of final assessment at 2 months, 20.5% of patients (N = 18) had not achieved normal levels of olfactory function. Higher baseline severity of olfactory loss measured using Sniffin-Sticks was strongly predictive of persistent loss (p < 0.001). Conclusion: In the first 2 months, 79.5% of patients may expect to have complete recovery of their olfactory function. The severity of olfactory loss, as detected at the first Sniffin-Sticks-test, may predict the lack of mid-term recovery.