Evaluation of subjective and tested olfactory dysfunction as a screening tool for COVID-19 in children.

INTRODUCTION: Olfactory dysfunction (OD) is an extremely frequent symptom of SARS-CoV-2 infection in adults. However, the symptomatology in the paediatric population remains understudied and heavily reliant on questionnaires. The aims of this study were to evaluate the prevalence of OD in children with SARS-CoV-2 infection and to assess the use of olfactory testing in predicting COVID-19 in children. Furthermore, we aimed to investigate the correlation between subjective and objective sense of smell in children. METHODS: Children aged 6-12 years presenting at Test Centre Aarhus for a reverse transcription PCR for SARS-CoV-2 were invited to participate during the study period (from 8 January to 22 February 2022). They underwent olfactory testing with Sniffin' Sticks 16 Identification Kit and they were asked about their subjective assessment of smell and any confounding factors. RESULTS: A total of 78 children completed inclusion of whom 51 had a positive SARS-CoV-2 PCR test. We found no correlation between either current SARS-CoV-2 status and Sniffin' Sticks Identification score (p = 0.500) or previous self-reported infection. We also found no correlation between subjective and objective sense of smell (p = 0. 109). CONCLUSION: The lack of correlation between SARS-CoV-2 infection and OD may indicate that OD is not a dominant symptom in children. Therefore, olfactory testing is not recommended as a screening method for SARS-CoV-2 as was suggested in adults. Likewise, subjective questioning is not a reliable tool in assessing olfactory function in children. FUNDING: Laura Danielsen received funding for salary from Forskningsfond Hospitalsenheden Vest (now Forskningsfond Regionshospitalet Gødstrup). Alexander Wieck Fjældstad wishes to acknowledge research salary funding for other projects from Velux Fonden. The sponsors had no say, roles or responsibilities in relation to the study, including (but not limited to) the study design, data collection, management, analysis or decision to publish. TRIAL REGISTRATION: Not relevant.

Olfactory training in long COVID-19 patients with lasting symptoms including olfactory dysfunction.

INTRODUCTION: Two-thirds of patients with COVID-19 developed smell and taste dysfunction, of whom half experienced improvement within the first month. After six months, 5-15% still suffered from significant olfactory dysfunction (OD). Before COVID-19, olfactory training (OT) was proved to be effective in patients with post-infectious OD. Therefore, the present study aimed to investigate the progress of olfactory recovery with and without OT in patients with long COVID-19. METHODS: Consecutive patients with long COVID-19 referred to the Flavour Clinic at Gødstrup Regional Hospital, Denmark, were enrolled. The diagnostic set-up at the first visit and follow-up included smell and taste tests, questionnaires, ENT examination and instructions in OT. RESULTS: From January 2021 to April 2022, 52 patients were included due to long COVID-19-related OD. The majority of patients complained of distorted sensory quality, in particular, parosmia. Two-thirds of the patients reported a subjective improvement of their sense of smell and taste along with a significant decline in the negative impact on quality of life (p = 0.0001). Retesting at follow-up demonstrated a significant increase in smell scores (p = 0.023) where a minimal clinically important difference (MCID) in smell scores was found in 23% of patients. Full training compliance was significantly associated with the probability of MCID improvement (OR = 8.13; p = 0.04). CONCLUSIONS: The average effect of OT is modest; however, full training compliance was significantly associated with an increased probability of a clinically relevant olfactory improvement. FUNDING: none. TRIAL REGISTRATION: not relevant.

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

INTRODUCTION: COVID-19 is causing a wide range of clinical manifestations. Severe complications and long-lasting sequelae have been identified. Thus, olfactory disorders are reported in up to 86% of cases in mild and moderate COVID-19 infections. We present the first study comparing simple and complex post-COVID-19 cases with matched non-COVID-19 post-infectious smell and taste disorders. METHODS: A total of 328 patients were recruited from the University Clinic for Flavour, Balance and Sleep, Ear-nose-throat Department, Goedstrup Hospital, Denmark. A non-COVID -19 post-infectious population of 148 individuals was identified from the Redcap database, and was matched by duration of smell and taste disorders. Post-COVID-19 patients were divided into 99 patients with simple smell and taste disorders (only suffering from smell and taste disorders after COVID-19); and (81 patients with complex smell and taste disorder plus several other post-COVID-19 complaints). Besides patient-reported outcome measures (PROM) questionnaires and quality of life score (QoL), ear-nose-throat examination, Mini-Mental State Examination (MMSE), orthonasal smell test (Sniffing's sticks), retronasal quick test, and taste screening were performed. RESULTS: Cases with post-COVID-19-related smell and taste disorders deviated from non-COVID-19 post-infectious cases; the patients were younger, had a lower occurrence of anosmia/ageusia, and had higher overall smell test scores. In contrast, patients with post-COVID-19-related smell and taste disorders more frequently complained of distorted senses. Parosmia and phantosmia were more prevalent among patients with simple post-COVID-19 complaints than among complex cases and their QoL were more negatively affected. CONCLUSION: Smell and taste function differ significantly between post-COVID-19 and other non-COVID-19 post-viral cases. LEVEL OF EVIDENCE: 3 Laryngoscope, 2022.