A widely-used antihistamine nasal spray for hay fever reduced COVID-19 infections by two-thirds in a phase 2 clinical trial. The study was published in JAMA Internal Medicine and may point towards an easy, low-cost way to prevent COVID-19.
Azelastine is widely used as an over-the-counter nasal spray for allergies. Recent studies have found that, beyond its antiallergic and anti-inflammatory properties, it has antiviral activity against a variety of respiratory viruses, including influenza A (H1N1) and SARS-CoV-2. Clinical trials have also found that azelastine reduces viral load in patients with confirmed SARS-CoV-2 infection.
In the current study, researchers investigated the efficacy and safety of azelastine for preventing SARS-CoV-2 infections in healthy adults. To do so, they recruited 450 participants and randomized them to receive azelastine nasal spray or a placebo three times per day for 56 days. They were tested for SARS-CoV-2 twice per week.
Ultimately, 2.2% of participants in the azelastine group became infected with SARS-CoV-2, whereas the same was true for 6.7% in the placebo group. Those taking azelastine also displayed fewer symptomatic SARS-CoV-2 infections, a lower number of confirmed respiratory infections, and a lower rate of rhinovirus infections. While 1.8% of those taking azelastine developed a rhinovirus infection, 6.3% in the placebo group developed the same.
“This clinical trial is the first to demonstrate a protective effect in a real-world setting. Azelastine nasal spray could provide an additional easily accessible prophylactic to complement existing protective measures, especially for vulnerable groups, during periods of high infection rates, or before travelling,” lead author of the study, Robert Bals, Professor of Internal Medicine at Saarland University, Germany, said in a press release.
“Our results highlight the need for larger, multicentre trials to continue exploring the use of azelastine nasal sprays as an on-demand preventive treatment, and to examine its potential effectiveness against other respiratory pathogens,” he added.
Sources: Science Daily, JAMA Internal Medicine