Results from a single-center randomized controlled trial published yesterday in JAMA Internal Medicine show that azelastine, an antihistamine nasal spray used as a preventive measure, was associated with a 69% reduction of COVID-19 infection.

Azelastine is a widely available over-the-counter treatment for seasonal allergies (hay fever).

“This clinical trial is the first to demonstrate a protective effect in a real-world setting,” said Robert Bals, MD, PhD, a professor at Saarland University in Germany and senior author of the study, in a university press release.