Azelastine Nasal Spray Significantly Reduces COVID-19 Infections in Phase 2 Trial

Saarbrücken, Germany - September 2, 2025 In a landmark phase 2 clinical trial, researchers at Saarland University Medical Center have found that regular use of the over-the-counter antihistamine azelastine nasal spray reduces the risk of SARS-CoV-2 infection by nearly two-thirds.

In the randomized, double-blind study involving 450 healthy adults, 227 participants self-administered azelastine nasal spray three times daily for 56 days, while 223 received a placebo. PCR-confirmed infections occurred in only 2.2% of the azelastine group compared with 6.7% of the placebo group-a threefold difference that underscores the spray’s protective efficacy against COVID-19.

Beyond COVID-19, the azelastine cohort also experienced fewer symptomatic respiratory infections overall. Rhinovirus infections, a common cause of colds, were reported in 1.8% of the treatment group versus 6.3% of those on placebo, suggesting broad antiviral benefits.

Azelastine has long been approved for allergic rhinitis relief, but in vitro studies hinted at its antiviral properties. This trial provides the first real-world evidence of its ability to prevent viral respiratory illnesses. Investigators hypothesize that azelastine may inhibit viral entry or replication by binding to viral particles in the nasal mucosa or by blocking the ACE2 receptor that SARS-CoV-2 uses to infect cells.

With its established safety profile and widespread OTC availability, azelastine nasal spray could serve as a practical adjunctive measure to vaccines and masks, especially during viral surges or for individuals with compromised immunity. Further large-scale, multicenter trials are planned to confirm these findings and elucidate the precise antiviral mechanisms.