The Risk of COVID-19 Infection in Individuals with Alopecia Areata.

OBJECTIVE

We sought to determine the risk of contracting coronavirus disease (COVID-19) in individuals with alopecia areata (AA) compared to individuals without AA.

METHODS

We queried the Symphony Health-derived data from the COVID-19 Research Database, and individuals with a diagnosis of AA from 2019 to 2020 were included in the AA cohort. Subjects with no record of AA diagnosis from 2019 to 2020 were randomly placed in the control group in a 4:1 size ratio compared with the AA group. Laboratory-confirmed cases of COVID-19 between January 1, 2020, and September 1, 2021, were identified.

RESULTS

The AA and non-AA cohorts included 73,784 and 280,991 subjects, respectively. The COVID-19 incidence rate ratio (IRR) for adults with AA was 0.72 (95% CI 0.68, 0.76) compared with adults without AA (p<0.001). Within the AA cohort, moderate-severe AA showed a similar decreased risk in COVID-19 infection compared to mild AA.

LIMITATIONS: This study is limited by its retrospective nature and the use of ICD-10 codes for the identification of individuals with AA and COVID-19, which may underestimate the true burden of disease.

CONCLUSION

Individuals with AA have a slightly decreased risk of contracting COVID-19. Notably, it has been demonstrated that interferon-gamma (IFN- γ) leads to the downregulation of the angiotensin-converting enzyme 2 (ACE2), the SARS-CoV receptor.1 Thus, it is possible that increased levels of IFN- γ seen in individuals with AA confer some protection against this viral infection.