Anosmia and dysgeusia associated with SARS-CoV-2 infection: an age-matched case-control study

Anosmia and dysgeusia have been reported as potential symptoms of coronavirus disease 2019. This study aimed to confirm whether anosmia and dysgeusia are specific symptoms among those who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

We conducted an age-matched case-control study in the Eastern Townships region of Quebec between Mar. 10 and Mar. 23, 2020. We included adults (age ≥ 18 yr) who tested positive for SARS-CoV-2 by reverse transcription polymerase chain reaction. Cases were matched (1:1) according to 5-year age groups with control patents selected randomly from among all patients who tested negative for SARS-CoV-2 during the same period. Demographic and laboratory information was collected from medical records. Clinical symptoms and comorbidities associated with anosmia and dysgeusia were obtained by telephone interview with a standardized questionnaire.

Among 2883 people tested for SARS-CoV-2, we identified 134 positive cases (70 women [52.2%] and 64 men [47.8%]; median age 57.1 [interquartile range 41.2-64.5] yr). The symptoms independently associated with SARS-CoV-2 positivity in conditional logistic regression were anosmia or dysgeusia or both (adjusted odds ratio [OR] 62.9, 95% confidence interval [CI] 11.0-359.7), presence of myalgia (adjusted OR 7.6, 95% CI 1.9-29.9), blurred vision (adjusted OR 0.1, 95% CI 0.0-0.8) and chest pain (adjusted OR 0.1, 95% CI 0.0-0.6).

We found a strong association between olfactory and gustatory symptoms and SARS-CoV-2 positivity. These symptoms should be considered as common and distinctive features of SARS-CoV-2 infection and should serve as an indication for testing and possible retesting of people whose first test result is negative.