07/10/2025
Clinical trial shows an allergy spray helps prevent COVID.
Scientists in Germany tested azelastine, a decades-old antihistamine spray usually prescribed for hay fever and dust allergies, to see if it could prevent viral infections.
In a clinical trial of 450 healthy adults, nearly all vaccinated, participants sprayed either azelastine or a placebo into their noses three times a day for eight weeks. The results were striking: only 2.2 percent of the azelastine group caught COVID-19, compared with 6.7 percent in the placebo group – a threefold difference.
And when infections did occur, they cleared faster: just over three days versus more than five.
Even more interesting, people using the spray were also less likely to catch other seasonal viruses like influenza or rhinovirus, and when they did, symptoms resolved more quickly.
Researchers think azelastine may interfere with how viruses attach to human cells in the nose, where many infections begin.
To be clear, this was a relatively small study, and azelastine is not approved by the FDA to prevent infections. Vaccines, masks in crowded spaces, and staying home when sick remain the best protections.
But the findings suggest that a cheap, over-the-counter spray – one already sitting on pharmacy shelves – could someday become an unexpected tool in reducing the spread of COVID-19 and other respiratory viruses.
Read the study:
"Azelastine Nasal Spray for Prevention of SARS-CoV-2 Infections: A Phase 2 Randomized Clinical Trial." JAMA, 2 Sep 2025.