Concordance of Anosmia Between Household Members Affected by COVID-19 Infection

Alterations in smell (anosmia) and taste (dysgeusia) are common with SARS-CoV-2. The study objective was to evaluate for concordance in anosmia and dysgeusia among household members affected by COVID-19.

A retrospective cohort study of individuals followed by the COVIDEO program at Sunnybrook Health Sciences Centre was performed for patients ≥4 years old diagnosed with COVID-19 between April 1, 2020, to December 31, 2020. Households were identified, and index cases were selected based on the first subject assessed by COVIDEO. Controls for each household contact were identified from the COVIDEO database by matching age (within 10 years) and date of diagnosis (closest within 3 months thereafter). Concordance of anosmia and dysgeusia was determined between index cases and household contacts compared to nonhousehold controls.

A total of 353 households were identified: 963 subjects (353 index cases, 600 household contacts) and 600 controls. Median age was 30 years (interquartile range [IQR]: 16, 49), and 50% (475/953) were women. Prevalence of anosmia and dysgeusia were 23.6% and 22.7%, respectively. Anosmia concordance was 64.3% between index cases and nonhousehold controls, compared to 65.7% (p = 0.09) between index cases and nongenetically related household members, and 69.4% (p = 0.74) between index cases and genetically related household members. In multivariate analysis, anosmia was more likely to be reported with longer time from symptom onset (OR 1.06 per day [95% CI 1.02 to 1.1]), and with rhinorrhea (OR 2.2 [95% CI 1.6 to 3.0]), or dyspnea (OR 2.4 [95% CI 1.3 to 4.4]).

There was no significant difference in anosmia and dysgeusia concordance between genetically related and unrelated household members or non-household controls.