Recent findings from a randomized controlled trial published in JAMA Internal Medicine reveal that azelastine, an antihistamine nasal spray typically used to prevent allergies, was linked to a significant 69% decrease in COVID-19 infections.
Azelastine is an easily accessible, over-the-counter option for those suffering from seasonal allergies, commonly known as hay fever.
This trial marks the first time a protective effect was documented in a real-world context.
Robert Bals, MD, PhD, a professor at Saarland University in Germany and senior author on the study, noted in a university press release, “This trial marks the first time a protective effect was documented in a real-world context.”
The study involved 450 participants, split into two groups. One group, consisting of 227 individuals, used the azelastine nasal spray three times daily for 56 days, while the other 223 received a placebo spray at the same frequency. The participants, all healthy adults aged 18 to 65, averaged 33 years old and included 66% women.
At the trial’s outset, everyone tested negative for an acute infection and had negative rapid antigen test results for SARS-CoV-2.
COVID-19 Rates in the Control Group
During the follow-up, 2.2% (5) of those in the azelastine group were infected with SARS-CoV-2 based on PCR testing, whereas 6.7% (15) in the placebo group contracted the virus.
This discrepancy results in a 69% reduction in COVID-19 incidence (odds ratio, 0.31; 85% confidence interval, 0.11 to 0.87).
Among those who did test positive, the azelastine group experienced a longer mean time before infection (31.2 days versus 19.5 days in the placebo group), along with fewer PCR-confirmed symptomatic infections (21 among 227 treated participants versus 49 among 223 who received the placebo).
Azelastine also significantly lowered rhinovirus infections in the treatment group, with only 1.8% developing a rhinovirus infection compared to 6.3% in the placebo group over the 56-day follow-up.
The occurrence of adverse events was similar in both groups.
The authors suggested, “These findings imply that azelastine might offer substantial protection against SARS-CoV-2 in a preventive context.” They also mentioned, “Existing data on the safety and efficacy of azelastine nasal spray formulations support its safe, long-term use.”
This approach that focuses on the nasal mucosa could be especially advantageous in areas where multiple respiratory viruses are circulating.
In a commentary on this study, Samuel Vidal, MD, PhD, and Dan Barouch, MD, PhD, both from Beth Israel Deaconess Medical Center in Boston, acknowledged the study’s potential but emphasized the need for further investigation among adults with existing health conditions. They noted that as variants evolve and vaccines adapt, addressing the nasal mucosa might be a promising strategy against COVID-19 during peak cold and flu seasons. They added, “Should these preliminary results be validated in larger phase 3 trials, azelastine could hold significant practical benefits due to its easy administration, affordability, and availability without a prescription.”
