Narrow Spray
Now, Moscona of Columbia University in New York City and her colleagues have found a compound that could thwart SARS-CoV-2. Even better, it just sprays on the nose – no needle injection is required.
The spray developed by the Moscona team is one of a series of proposed nasal sprays to prevent SARS-CoV-2 infection. These sprays take effect quickly and will be used frequently, perhaps once or twice a day, for the first place where the virus is rooted—the endoscopic membrane and the throat.
Unlike vaccines that induce the receptor immune system to establish lasting protection, sprays are short-acting compounds that directly block the virus's ability to enter cells. Multiple research teams have shown that this spray is effective against SARS-CoV-2 infection in animals.
If effective in humans, these compounds would be a welcome addition to a limited arsenal of weapons developed by researchers against the virus, said Donna Farber, an immunologist at Columbia University in New York City. Vaccines can prevent severe COVID-19, but they are not very good at preventing infections, with current antiviral treatments rather than preventing infections.
spray can provide people with another way to avoid infection, especially in high-risk environments such as hospitals and restaurants, especially in high-risk environments such as hospitals and restaurants. “They are definitely worth pursuing,” she said.
Although they are promising, these sprays have a long way to go: Pharmaceutical companies have limited funding and interest in human trials, partly because trials that determine the effectiveness of preventive drugs are large and expensive, Moscona said.
spray must accomplish a difficult task of coating any surface that the virus may attach to, because once the virus particles enter even a few cells, a full infection develops rapidly.
Virus blockade
Virologist Wendy Barclay, London, said efforts to develop preventive treatments for the virus had existed long before COVID-19.
These studies have been rewarded with oral administration of a range of drugs, including oseltamivir (Daffe) to prevent influenza infection and tenofovir-emtricitabine to prevent HIV infection. But, Barclays says there is no preventive nasal spray besides First Defense, which is designed as a physical barrier against common cold virus particles.
preventive sprays are simpler than traditional antiviral drugs used in the first few days of infection, such as Paxlovid: Preventing a single viral particle from infecting cells is an "easier requirement than offsetting the effects of millions of viral particles," Barclays said.
Researchers have been testing multiple types of compounds in nasal sprays to prevent SARS-CoV-2 infection. These include small antibody-like molecules called nano-antibodies that disarm the virus by nestling in the nooks and crannies of viral proteins; short chains of amino acids called peptides; and small molecules that mimic proteins.
For example, the preventive measure developed by Moscona and her colleagues is a peptide that binds the mechanism by which the virus fusion with the host cell. This prevents the virus from passing its genetic payload into the cells, thus preventing infection.
To test their peptides, Moscona and her colleagues put them in the nose of ferret once a day for two days and co-raising treated animals with another ferret infected with SARS-CoV-2.
None of the six ferrets receiving the peptide were infected with the virus, while all six ferrets receiving the placebo dose were infected with the virus. 1. Before testing peptides in humans, Moscona hopes to replicate these results in another animal model, such as mice.
Another nasal spray compound developed by Richard Leduc, a molecular pharmacist at the University of Sherbrook, Canada, and colleagues, is a small molecule that inhibits the host enzymes needed for the fusion of viral particles to target cells. Leduc and his colleagues found that mice given nasal doses of compounds were infected with coronavirus, but their lungs had much less viruses than mice that received saline only.
Leduc and his colleagues are working to improve the effectiveness of the peptides, making them more stable and selective before continuing to test humans. Leduke and Moscona are working with the company to bring their products to market.
runny nose affects drug efficacy
Even if researchers found an antiviral compound that can be delivered as a nasal spray and prevent human coronavirus from infecting , they still face the challenge of ensuring that the compound stays in the endosterior membrane long enough to always be effective. “Your nose and throat are essentially designed to get rid of things,” Barclays said. "You try to put things in, your nose flows out, rinse it out.
researchers can offset this by designing the reuse of sprays more frequently, but Barclays warn that the more often people have to take medication, the less likely they are to stick to the regimen. Although most SARS-CoV-2 infections start with the nose, there may be a need for preventive drugs to cover the mouth and throat and even the lungs, which needs to be delivered through a nebulizer.
Still, this spray will be an important advance, especially where few people wear masks, Barclays says. "If we have something invisible and you manage yourself, it gives you the confidence to keep going, I think it will be a real game changer," she said. "We can keep kids at school."
References
De Vries, R. D., et al. Science 371, 1379–1382 (2021).
Shapira, T., et al. Nature 605, 340–348 (2022).
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