"Can 'Pollen Allergy Spray' Keep Viruses Away? Groundbreaking Research Results on Preventing COVID-19 Infection: The Potential of Azelastine Nasal Spray"

"Can 'Pollen Allergy Spray' Keep Viruses Away? Groundbreaking Research Results on Preventing COVID-19 Infection: The Potential of Azelastine Nasal Spray"

2025年09月09日 01:18

Introduction──Spotlight on "Pollen Allergy Spray" Again

"We continue with masks and ventilation, but isn't there more 'self-prevention' we can do?" In response to such sentiments, nasal spray for allergies has re-emerged as a focus during the infectious disease season. The core of the topic reported by Germany's RP ONLINE is the JAMA Internal Medicine publication on September 2, 2025, regarding the Phase II randomized placebo-controlled trial of azelastine nasal spray. The results are simple and memorable: infection rate: 2.2% vs. 6.7%. The relative risk is about one-third. We will interpret the study's design, limitations, and practical implications, incorporating primary information, expert commentary, and social media reactions.JAMA NetworkPMC


What Was Demonstrated──Trial Design and Key Results

The study was conducted at a single facility, Saarland University Hospital in Germany, involving 450 healthy adults aged 18-65, randomly assigned 1:1 to the azelastine 0.1% group (227 people) and the placebo group (223 people). They sprayed three times a day for 56 days, and endpoints were determined by twice-weekly antigen tests and PCR confirmation. The primary endpoint was "SARS-CoV-2 infection confirmed by PCR." The results showed 2.2% in the azelastine group compared to 6.7% in the placebo group. There was also a reduction in respiratory symptoms and duration of illness, and a tendency to suppress infections like rhinovirus and non-SARS-CoV-2 was observed. Serious adverse events were not prominent, and tolerability was generally good.JAMA NetworkPMC


How It Works──The "Dual Role" of Antihistamines

Azelastine is originally a second-generation antihistamine that suppresses inflammation (sneezing, runny nose, nasal congestion) in allergic rhinitis. However, at the experimental level, it has been reported to have a "virus-like" action that interferes with the viral entry and replication process. The dual effect of soothing nasal mucosal inflammation and reducing the foothold for viruses works at the forefront of the "battlefield" of the upper respiratory tract—this hypothesis was first realized as a preventive effect in this trial. Previous reports have also suggested treatment-oriented effects such as reduction in viral load and shortening of the excretion period.PMC


Caution──Avoid "Excessive Generalization"

Behind the impressive numbers, there are limitations. The study was single-center and medium-sized (Phase II), focusing on young to middle-aged healthy adults. The authors clearly state that the possibility of breaking the blind due to azelastine-specific side effects like bitterness and the **"barrier effect"** of excipients in the placebo cannot be completely ruled out. In other words, the conclusion is "promising but not definitive." Follow-up studies in multi-center, multinational, and more diverse populations are essential.PMC


Practical Implications──"Addition" Rather Than "Replacement"

How to incorporate this achievement into daily life? The CIDRAP at the University of Minnesota positions it as a "promising additional measure" while clarifying that it does not replace vaccination, ventilation, masks, and hand hygiene, which are fundamental measures. Particularly, the use as **"on-demand prevention" during high-risk times (such as travel, events, before and after medical visits) seems reasonable. Experts from WebMD and universities also introduce it as "one of the options."**CIDRAPWebMDUniversity of Cincinnati


The Context of Preceding "Nasal Prevention"

During the pandemic, products based on the idea of "stopping the virus in the nasal cavity", such as carrageenan (derived from red algae) and cellulose-based barrier sprays, gained attention. However, the quality of products and trials was mixed, and the general conclusion was that evidence of effectiveness was limited. The azelastine study stands out with its robust design and publication in a major journal, but the final answer is still forthcoming.PMCDIE WELT


Price and Availability──The Strength of "Already on the Shelf" Medicine

Azelastine is distributed as an OTC (over-the-counter) medication in various countries and is well recognized as a staple for pollen allergies. It has extensive existing safety data and is relatively low in cost. These strengths of being "immediately testable" will likely be more applicable to individual-level risk management rather than population-level infection control. However, since usage and approval scope vary by country and region, adherence to label instructions and consultation with healthcare providers is essential.CIDRAP


Social Media Reactions──Reading the "Fluctuations" in Enthusiasm

 


X (formerly Twitter) and Reddit, Mastodon saw a surge in related articles and threads immediately after the study's release.

  • Proponents: "'An easily accessible preventive measure has increased'," "I want to use it before events," with voices evaluating it as an additional layer. Official accounts of media and academic journals also summarized and disseminated the results.X (formerly Twitter)X (formerly Twitter)

  • Cautious Voices: Comments touching on statistical uncertainty, such as "single-center Phase II with limited external validity" and "wide confidence intervals." Some Reddit threads predominantly concluded that **"the effect is merely at a level of reduction."**Reddit

  • Comparison Voices: References to carrageenan and steroid nasal sprays, which were previously in the spotlight, appeared frequently, with the observation that **"defense from the nose is a consistent concept."**Reddit

Overall, the sentiment that it is not a "magic bullet" but rather a "realistic additional measure" was visualized.


Points to Note When Using (General Information)

  • Do Not Replace: It is not a substitute for vaccines, ventilation, masks, or hand hygiene.Allergieinformationsdienst

  • Timing: Use on-demand before and after high-exposure scenes such as crowds, long-distance travel, and indoor events. The trial was three times a day for 56 days, but for personal use, follow the label instructions.JAMA Network

  • Side Effects: Bitterness, nasal irritation, etc. If you have chronic illnesses or are taking other medications, consult a healthcare provider.JAMA Network##

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