dcyphr | Features of anosmia in COVID-19


The scientists aimed to describe the prevalence and characteristics of anosmia in patients with confirmed COVID-19, as it has been rarely described in medical literature. 


The scientists conducted a retrospective observational study in which they included COVID-19 patients with anosmia. They used SARS-CoV-2 real time PCR on respiratory samples to confirm the cases. The scientists called non-hospitalised and discharged patients seven days (± 7 days) after the first symptoms and every week until recovery to monitor clinical outcome. The scientists used usual descriptive statistics. 


Fifty-four of 114 patients (47%%) with confirmed COVID-19 reported anosmia. Mean age of the 54 patients was 47 (± 16) years. Thirty-six (67%%) were females. Twenty of the patients (37%%) were hospitalised. Fifteen (28%%) patients with COVID-19 received a clinical diagnosis of pneumonia. Forty-six patients (85%%) had dysgeusia. Anosmia began 4.4 (± 1.9 [1–8]) days after infection onset and lasted 8.9 (± 6.3 [1–21]) days. Only one patient did not recover from anosmia after 28 days. Anosmia was the third symptom in 38%% (22/52) of cases. In Figure 1 scientists show that the duration of anosmia was ≥ 7 days for 55%%and ≥ 14days for 20%% of patients.


This study seems to be the main monocentric cohort of confirmed COVID-19 patients with anosmia in France and in the medical literature. The scientists had similar results to those published by the recent multicentric European study by Lechien et al. Anosmia was a frequent symptom in COVID-19 patients in both studies. The scientists discussed the differences between Asia and Europe, as in Asia there are only a few descriptions of ENT symptoms available. Their assumptions included the theoretical possibility of a mutation of SARS-CoV-2 viral genome associated with a clinical impact, as well as, the difficulty to precisely report ENT symptoms of critical patients. The scientists considered that the limited number of patients was a limitation of the study.


The scientists detected anosmia in half of their European COVID-19 patients. In more than 80%% of cases anosmia was associated with dysgeusia. Most patients (98%%) recovered from anosmia after 28 days.