Setting
Adult patients with confirmed COVID-19 and self-reported sudden-onset
olfactory dysfunction were recruited through a public call from the
Department of Anatomy of the University of Mons (Mons, Belgium). To be
included, patients had to be not currently hospitalized
(mild-to-moderate patients). The diagnosis of COVID-19 infection was
based on the WHO interim guidance and symptoms of disease [8].
Individuals with self-reported sudden olfactory dysfunction and a
clinical history suggestive of COVID-19 were invited to participate. A
nasopharyngeal swab was performed
to identify severe acute respiratory coronavirus-2 (SARS-CoV-2) via
reverse transcription polymerase chain reaction (RT-PCR) for patient
with symptom duration<14 days. In case of negative RT-PCR,
serology for IgG and IgM to SARS-CoV-2 was realized. For patients with
symptom duration ≥14 days, physicians performed serology (Figure 1).
Only patients with a RT-PCR positive test or with positive IgG or IgM
were included. Patients with a history of olfactory dysfunction before
the pandemic, history of nasal surgery, chronic rhinosinusitis, head &
neck trauma, or degenerative neurological disease were excluded from the
study.