Subjective Smell Disturbances in Children with Sars-Cov-2 or Other Viral Infections do not Correspond with Olfactory Test Results

Abstract

Background Olfactory dysfunction associated with SARS-CoV-2 infection in children has not been verified by a validated olfactory test. We aimed to determine whether these complaints are objectifiable (test-based hyposmia), how often they occur during acute SARS-CoV-2 infection compared to other upper respiratory tract infections (URTI), as well as in children recovered from COVID-19 compared to children with long COVID.

Methods Olfactory testing (U-sniff test; hyposmia<8 points) and survey-based symptom assessments were performed in 434 children (5–17 years; 04/2021–06/2022). 186 symptom-free children served as controls. Of the children with symptoms of acute respiratory tract infection, SARS-CoV-2 PCR test results were positive in 45 and negative in 107 children (URTI group). Additionally, 96 children were recruited at least 4 weeks (17.6±15.2 weeks) after COVID-19, of whom 66 had recovered and 30 had developed long COVID.

Results Compared to controls (2.7%), hyposmia frequency was increased in all other groups (11–17%, p<0.05), but no between-group differences were observed. Only 3/41 children with hyposmia reported complaints, whereas 13/16 children with complaints were normosmic, with the largest proportion being in the long-COVID group (23%, p<0.05).

Conclusion Questionnaires are unsuitable for assessing hyposmia frequency in children. Olfactory complaints and hyposmia are not specific for SARS-CoV-2 infection. The number of complaints in the long-COVID group could result from aversive olfactory perception, which is undetectable with the U-sniff test.

Zusammenfassung

Hintergrund Geruchsstörungen im Zusammenhang mit einer SARS-CoV-2-Infektion bei Kindern wurden bisher nicht durch einen validierten Geruchstest untersucht. Ziel dieser Studie war es, festzustellen, ob diese Beschwerden objektivierbar sind (testbasierte Hyposmie), ob sie bei einer akuten SARS-CoV-2-Infektion häufiger auftreten als bei anderen Infektionen der oberen Atemwege (URTI) und ob sich die Häufigkeit bei Kindern, die sich von COVID-19 erholt haben, im Vergleich zu Kindern mit Long-COVID unterscheiden.

Methoden Geruchstestung (U-Sniff-Test; Hyposmie<8 Punkte) und umfragebasierte Symptomerfassung wurden bei 434 Kindern (5–17 Jahre; 04/2021–06/2022) durchgeführt. 186 symptomfreie Kinder dienten als Kontrollen. Von den Kindern mit Symptomen einer akuten Atemwegsinfektion waren die Ergebnisse des SARS-CoV-2 PCR-Tests bei 45 Kindern positiv und bei 107 negativ (URTI-Gruppe). Zusätzlich wurden 96 Kinder mindestens 4 Wochen (17,6±15,2 Wochen) nach COVID-19 rekrutiert, von denen 66 genesen waren und 30 Long-COVID entwickelt hatten.

Ergebnisse Im Vergleich zur Kontrollgruppe (2,7%) war die Häufigkeit einer Hyposmie in allen anderen Gruppen erhöht (11–17%, p<0,05), aber es wurden keine Unterschiede zwischen den Gruppen festgestellt. Nur 3/41 Kinder mit Hyposmie berichteten über Beschwerden, während 13/16 Kinder mit Beschwerden normosmisch waren, mit dem größten Anteil in der Long-COVID-Gruppe (23%, p<0,05).

Schlussfolgerung Fragebögen sind für die Beurteilung der Hyposmiehäufigkeit bei Kindern ungeeignet. Geruchsbeschwerden und Hyposmie sind nicht spezifisch für eine SARS-CoV-2-Infektion. Die häufigen Beschwerden in der Long-COVID-Gruppe könnten auf eine mit dem U-Sniff-Test nicht nachweisbare, aversive Geruchswahrnehmung zurückzuführen sein.

Key words

Long COVID - URTI - U-sniff test - hyposmia - survey - SARS- CoV- 2

Schlüsselwörter

Hyposmie - long COVID - Fragebogen - U-sniff test - Atemwegsinfekt - SARS- CoV- 2

Publication History

Article published online:
23 January 2024

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