The effect of quercetin on the prevention or treatment of COVID-19 and other respiratory tract infections in humans: A rapid review

Monique Aucoin; Kieran Cooley; Paul Richard Saunders; Valentina Cardozo; Daniella Remy; Holger Cramer; Carlos Neyre Abad; Nicole Hannan

doi:10.1016/j.aimed.2020.07.007

The effect of quercetin on the prevention or treatment of COVID-19 and other respiratory tract infections in humans: A rapid review

Adv Integr Med. 2020 Dec;7(4):247-251. doi: 10.1016/j.aimed.2020.07.007. Epub 2020 Jul 30.

Authors

Monique Aucoin¹, Kieran Cooley^{1

2

3}, Paul Richard Saunders¹, Valentina Cardozo¹, Daniella Remy¹, Holger Cramer^{2

4}, Carlos Neyre Abad⁵, Nicole Hannan⁶

Affiliations

¹ Canadian College of Naturopathic Medicine, Toronto, Ontario, Canada.
² Australian Research Centre in Complementary and Integrative Medicine, University of Technology Sydney, New South Wales, Australia.
³ Pacific College of Health Sciences, San Diego, California, United States.
⁴ Department of Internal and Integrative Medicine, Kliniken Essen-Mitte, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany.
⁵ University of California, Los Angeles, Los Angeles, California, United States.
⁶ School of Pharmacy and Pharmacology, Griffith University, Gold Coast, Queensland, Australia.

Abstract

Brief overview: There is currently insufficient evidence to recommend quercetin supplementation as a therapy for the treatment or prevention of COVID-19. Three human clinical trials with low risk of bias suggest that oral quercetin may have a beneficial effect on the incidence and duration of respiratory tract infections in certain populations; however, further research is needed.

Verdict: Current evidence on the efficacy of quercetin supplementation in the treatment and prevention of COVID-19 is insufficient for its clinical recommendation at this time. Quercetin exhibits both immunomodulatory and antimicrobial effects in preclinical studies; however, only three human clinical trials, each with a low risk of bias rating, were identified in this rapid review. One study reported a decrease in incidence of upper respiratory tract infections following a competitive athletic event. A larger community clinical trial reported a benefit in older, athletic adults only.

Keywords: COVID; COVID-19; Quercetin; Rapid review; Respiratory tract infection.