The active ingredient in a common over-the-counter allergy spray may do more than ease hay fever symptoms. A new clinical trial found azelastine cut COVID-19 infections by 70%, hinting at a cheap, accessible way to add protection alongside vaccines.
Let’s be honest: when it comes to COVID-19 prevention, the conversation usually starts and ends with vaccines. But researchers say your everyday allergy spray might have a surprising new role.
A Phase 2, randomized, double-blind, placebo-controlled clinical trial led by researchers from Saarland University in Germany has found that a widely used over-the-counter (OTC) anti-allergy nasal spray containing azelastine not only significantly reduced the likelihood of people being infected with the SARS-CoV-2 virus, but it also lowered the incidence of infections with the common cold.
“This clinical trial is the first to demonstrate a protective effect in a real-world setting,” said Professor Robert Bals, MD, Director of Saarland’s department of Pulmonology, Allergology, Respiratory Intensive Care and Environmental Medicine. “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 traveling.”
The researchers recruited 450 healthy adults, with an average age of around 33, into the trial. Almost all participants had been vaccinated against COVID-19. They were randomly assigned to receive either azelastine (0.1%) nasal spray or placebo. They used the spray three times a day for 56 days. In cases of coronavirus exposure or symptoms, participants could increase the dose to five times daily for three days. They were tested for COVID-19 with rapid antigen tests (RATs) twice weekly. Positive results were confirmed with PCR. If a participant had symptoms but a negative RAT, they were tested for a wide range of respiratory viruses.
In the azelastine group, 2.2% of participants became infected with COVID-19 vs. 6.7% in the placebo group. This means azelastine users had about a 70% lower risk of getting infected with the virus. There were also fewer symptomatic COVID cases in the azelastine group (1.8% vs. 6.3%). It took longer for those in the treatment group to catch the virus compared to the placebo group; an average of 31 days vs. 19 days. And, the azelastine group had a lower incidence of infection with the common cold (rhinovirus). Overall respiratory infections in the azelastine group were 9.3% vs. 22% in the placebo group. Side effects were generally mild and already known for azelastine, such as bitter taste, occasional nosebleeds, and tiredness. Serious adverse events occurred rarely and, the researchers said, weren’t linked to using the nasal spray.
Nasal sprays with azelastine as the active ingredient can be bought OTC in the US and Australia. The 0.15% azelastine nasal spray under the brand Astepro Allergy is available in the US; it’s the first OTC prescription-strength antihistamine nasal spray approved by the FDA. In Australia, Azep Nasal Spray (azelastine 0.1%) is available OTC. In the UK, azelastine nasal sprays, such as Rhinolast (0.1%) and Azelair (0.15%), can only be obtained with a prescription.
The study had some limitations. The trial sample size of 450 participants is modest; larger studies are needed. Further, the trial was conducted at a single German hospital, so the findings may not be generalizable to all populations. Importantly, participants were mostly young, healthy, White, and already vaccinated against COVID-19. Results may differ in unvaccinated or high-risk groups. Also, the reliance on RATs might have missed some asymptomatic COVID infections. And even using a placebo spray may have had some protective effects by rinsing and coating the nasal lining.
Nonetheless, azelastine is already available OTC and has a long safety record. It’s cheap, widely available, and easy to use. It has the potential to be used as a prophylactic to reduce the incidence of COVID-19 and other respiratory infections, particularly in high-risk settings such as crowded events, travel, and healthcare settings. While azelastine is unlikely to replace vaccines, it may complement vaccination by providing an additional layer of protection, particularly against breakthrough infections. Further research is needed.
“Our results highlight the need for larger, multicenter 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,” Bals said.
The study was published in the journal JAMA Internal Medicine.
Source: Saarland University
