A new study has revealed that individuals using an allergy medication were significantly less likely to get infected with COVID-19 and the common cold. This research adds to the growing evidence supporting the efficacy of nasal sprays in combating respiratory viruses right at their entry point.
“It would be fantastic if we could stop the virus at our nose—our first line of defense,” said Dr. William Schaffner from the Vanderbilt University School of Medicine in Nashville.
The German study, which involved 450 adults and was published on September 2, concluded that participants taking azelastine, an antihistamine available under the brand names Astepro and Astelin, had a considerably lower risk of viral infections compared to those on a placebo. This follows other recent studies hinting that various nasal sprays could help prevent the spread of respiratory viruses.
Dr. Schaffner, who wasn’t part of the study, emphasized the need for more comprehensive testing since the initial study had a relatively small sample size and relied on animal trials. He mentioned that larger studies will clarify the real-world effectiveness of these sprays, including the correct dosages and frequency of use.
KEY FINDINGS
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Recent research has been pointing towards the potential of nasal sprays in preventing COVID-19, influenza, and the common cold, but more extensive studies are necessary for validation.
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A recent study indicated that azelastine significantly lowered the chances of falling ill from COVID-19 or the common cold, suggesting it could be beneficial to use before attending high-risk situations.
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New gels are in development that may nearly prevent virus transmission, but they would need to be applied multiple times a day—a requirement that may be impractical for long-term use.
Dr. Schaffner noted that for viruses to make a person sick, they need to attach to and enter cells, with the nose being the primary entry point for respiratory viruses. Treatments delivered nasally could potentially be more effective than those administered through injections, as they target the virus right at its source.
He also mentioned that funding cutbacks during the Trump administration could hinder the development of nasal vaccines by diverting resources from these projects.
In the study, those using azelastine did so three times daily over an average period of 56 days. Findings suggested they were roughly three times less likely to contract COVID-19 or rhinoviruses, which are linked to the common cold, compared to non-users. A previous, smaller investigation into azelastine had similar results.
Initial Doubts About Antihistamines
Antihistamines function by blocking the chemical responsible for allergic responses. During the early days of the COVID-19 pandemic, Dr. Sharon Nachman from Stony Brook Medicine expressed skepticism about their potential to defend against the virus, noting, anecdotally, that it “did not seem to make a difference.”
However, she pointed out that with the prevalence of either COVID-19 infections or vaccinations among the population now, the immune response may be different from what it was before.
Dr. Nachman advised against using azelastine specifically for COVID-19 or colds until more extensive studies are conducted and interpreted.
There have been varying results in investigating other nasal spray options, including those derived from nitric oxide and red seaweed.
Nasal spray research isn’t a novel concept; FluMist, a federal-approved nasal spray used for flu vaccination, has been around since 2003 and is reported to be as effective as traditional injections, according to Dr. Schaffner.
Increased focus on nasal sprays recently can be attributed to efforts to develop more effective COVID-19 vaccines, noted Dr. Paul Spearman from Cincinnati Children’s Hospital Medical Center. Current COVID-19 vaccines are good at preventing severe disease, but their ability to stop transmission diminishes weeks after vaccination.
“Ideally, if a vaccine could prevent initial infections and the spread, it would be a significant improvement over our current options,” Dr. Spearman stated.
Promising Gel Developments
Researchers from Harvard Medical School and Brigham and Women’s Hospital announced last year that they had created a gel-like spray that coats the nasal passages and was nearly 100% effective in blocking viruses from infecting mice, and also in a 3D model of the human nose.
Other studies are also looking into gels, but maintaining their effectiveness requires regular application. In Harvard’s findings, the gel remained protective for up to eight hours. Dr. Spearman expressed doubt that people would reapply such a gel multiple times daily for extended periods to ward off colds or COVID-19.
The azelastine study similarly indicates a need for ongoing usage for effective protection. The authors hinted it could be particularly useful before entering “high-risk environments, like large gatherings or travel.” Yet again, more research is needed to ascertain the optimal usage pattern.
Dr. Spearman also led a recent U.S. clinical trial for a nasal COVID-19 vaccine that indicated higher doses resulted in significantly lower symptoms among participants compared to those on a lower dose. He believes a larger study will be necessary to further substantiate these findings.
He concluded that eliciting an immune response in the nose offers considerable promise. “If that happens, your immune cells can effectively neutralize the virus before it progresses, ideally preventing it from reaching the lungs or causing illness elsewhere,” he explained.
