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Trial finds significant drop in SARS‑CoV‑2 and common cold cases
A randomized, double‑blind phase 2 clinical trial led by Professor Robert Bals at Saarland University Medical Center found that regular use of an over‑the‑counter azelastine nasal spray reduced confirmed SARS‑CoV‑2 infections by roughly two‑thirds compared with placebo. The CONTAIN study enrolled 450 adult volunteers and split them into two arms: 227 participants self‑administered azelastine nasal spray three times daily for 56 days, while 223 participants received a placebo spray on the same schedule. All infections were confirmed by PCR testing.
Over the 56‑day observation window, 2.2% of participants in the azelastine arm tested positive for SARS‑CoV‑2, versus 6.7% in the placebo arm. The treatment group also experienced fewer symptomatic COVID‑19 cases and a lower total number of PCR‑confirmed respiratory infections. Unexpectedly, the azelastine group saw a similar reduction in rhinovirus infections — a common cause of colds — with 1.8% affected compared with 6.3% in the placebo group.
Why azelastine might work: background and laboratory evidence
Azelastine is a long‑established antihistamine sprayed into the nose to treat allergic rhinitis (hay fever) and has been sold over the counter for decades. Prior in vitro studies suggested that azelastine can inhibit replication of SARS‑CoV‑2 and other respiratory viruses in cell cultures, offering a plausible antiviral mechanism in addition to its antihistamine action. The CONTAIN trial is, according to the investigators, the first randomized clinical study to show a protective effect against respiratory virus infections in a real‑world setting.
Professor Bals and colleagues interpret the findings cautiously but optimistically. They propose that azelastine nasal spray could serve as an accessible, low‑cost adjunctive prophylactic—particularly for people at higher risk of severe disease, during seasonal peaks of respiratory viruses, or before travel or high‑exposure events. However, the team emphasizes that these results are preliminary and that larger, multicentre trials are necessary to confirm effectiveness, define optimal dosing and duration, and test activity against a broader range of respiratory pathogens.
Study collaborators, design and implications for public health
The CONTAIN trial involved multiple academic groups and industry partners: Saarland University Medical Center; the Institute of Clinical Pharmacy (Professor Thorsten Lehr, Dr. Dominik Selzer); the Institute of Virology (Professor Sigrun Smola); the Helmholtz Institute for Pharmaceutical Research Saarland (HIPS); and URSAPHARM Arzneimittel GmbH of Saarbrücken, which sponsored the study and manufactured the investigational product. The randomized, double‑blind design and PCR confirmation of infections strengthen confidence in the reported effect size, but the phase 2 sample remains modest for broad public‑health recommendations.
Expert Insight
Dr. Elena Martínez, an infectious‑disease physician and science communicator, commented: 'The reduction in both SARS‑CoV‑2 and rhinovirus is intriguing because it suggests a non‑specific antiviral effect at the nasal mucosa — the entry point for many respiratory viruses. If replicated in larger trials, azelastine could become a practical, inexpensive tool for short‑term risk reduction. That said, it should complement, not replace, vaccination, ventilation, and established hygiene measures.'
Conclusion
The phase 2 CONTAIN trial indicates that a commonly available azelastine nasal spray may substantially lower the risk of PCR‑confirmed SARS‑CoV‑2 infection and reduce incidence of rhinovirus infections. While promising as an easy, low‑cost preventive option, the findings require confirmation in larger, multicentre studies to determine best practices, safety over longer use, and effectiveness across different populations and viral variants. For now, azelastine could be considered an adjunctive measure pending further clinical evidence.
Source: sciencedaily
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