Recent findings published in the Proceedings of the National Academy of Sciences demonstrate the potential of intranasal neomycin to elicit broad-spectrum antiviral immunity in the upper respiratory tract.
The new study highlights the drug's ability to induce interferon-stimulated genes, providing significant protection against upper respiratory infections in animal models, including a mouse model of COVID-19 and influenza, as well as in SARS-CoV-2 transmission among Syrian hamsters.
Neomycin, a commonly used aminoglycoside antibiotic, was repurposed in this study to explore its host-directed antiviral properties. The researchers found that even a single intranasal application could rapidly induce (interferon-stimulated gene) ISG expression, independent of the commensal microbiota. This induction was sufficient to decrease viral load and increase survival rates significantly in the tested models.
Importantly, the effects of neomycin were observed to be independent of type I and III interferon receptor signaling, suggesting a novel mechanism of antiviral action that could potentially circumvent the development of drug-resistant viral strains. This aspect of the study could have significant implications for the treatment of respiratory viruses, which often mutate, rendering targeted antiviral treatments less effective over time.
“Our findings suggest that we might be able to optimize this cheap and generic antibiotic to prevent viral diseases and their spread in human populations, especially in global communities with limited resources,” wrote the study researchers. “This approach, because it is host-directed, should work no matter what the virus is.”
In addition to its efficacy in animal models, a pilot human study involving intranasal application of Neosporin—a commercially available ointment containing neomycin—showed promising results. The treatment was well tolerated, and a subset of participants exhibited increased ISG expression, further supporting the potential utility of neomycin as a preventive strategy against respiratory viral infections in humans.
“Our study highlights a previously unexplored treatment modality that evokes protective antiviral immunity in the upper airway using preclinical animal models and randomized controlled human studies. We envision this simple yet effective strategy to be readily deployed in resource-limited, developing countries to combat respiratory viral diseases,” the researchers wrote.
The study was funded by the Melinda and Bill Gates Foundation. The authors disclosed potential conflicts of interest, noting that one of the lead researchers, Akiko Iwasaki, has affiliations with multiple biotechnology companies.
