Nasal spray provides effective COVID-19 protection

Finnish researchers have developed a molecule that is, when administered nasally, extremely effective in preventing the disease caused by all known variants of the SARS-CoV-2 virus. Described in the journal Nature Communications, the molecule could be a key tool in preparing for future pandemics as it is aimed at preventing both the transmission and spread of the virus.

Known as TriSb92 and developed by researchers at the University of Helsinki, the molecule works by identifying a region in the spike protein of the coronavirus common to all current variants of the virus and inhibiting its functioning. Laboratory animal studies have confirmed that the molecule affords effective protection against coronavirus infection when sprayed into the nose, even after a few hours of exposure.

“When administered nasally, the TriSb92 molecule is extremely effective in preventing infection, and experiments carried out in cell cultures indicate that it also encompasses the very latest variants, including XBB, BF7 and BQ.1.1,” said postdoctoral researcher Anna R Mäkelä. The molecule could therefore be crucial in preventing the spread of the virus in the future.

“The latest variants effectively avoid the immune protection provided by both vaccines and the COVID-19 disease, and current vaccines are not effective in preventing transmission,” Mäkelä noted. The nasal spray could thus protect from serious disease those who do not gain sufficient immunity from vaccines, such as immunocompromised individuals and the elderly, and could also work against future animal-borne close relatives of SARS-CoV-2.

“Since the region in the coronavirus’s spike protein affected by the TriSb92 molecule has remained almost unchanged in all viral variants so far emerged, it can be assumed to be effective also against future SARS-CoV-2 variants,” Mäkelä said.

“The easily and inexpensively produced TriSb92 could be a very important first line of defence in curbing such a new pandemic, pending the development, production and distribution of vaccines.”

The researchers said the molecule remains fully functional at room temperature for at least 18 months, making it well suited for use as a nasal spray. The technology is also applicable to the prevention of many other viral diseases, particularly influenza and other respiratory viruses.

“The whole approach stems from a technical solution based on a binder protein platform developed in Finland, which was not originally intended for the development of an antiviral drug,” Mäkelä said. “It provides an opportunity for many other new initiatives based on the accurate identification of diseased cells or pathogens in patients.”

In the next stage, the molecule must be tested in clinical trials, after which it could be made commercially available.

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