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, including the currently circulating XBB variant.

The molecule, known as TriSb92, can be a key tool in preparing for future pandemics, as it is aimed at preventing both the transmission and spread of the virus, said researchers from the University of Helsinki in Finland.

They found that TriSb92 identifies a region in the spike protein of the Covid common to all current variants of the virus and inhibits its functioning. Further, animal models have demonstrated that, unlike face masks, the molecule can, when sprayed into the nose, prevent infection 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 Anna R. Makela, postdoctoral researcher at the varsity.

In the paper, published in the journal Nature Communications, the researchers said that the molecule remains fully functional at room temperature for at least 18 months, making it well suited for use as a nasal spray.

While the worst stage of the coronavirus pandemic is, at least for the time being, behind us, nasally administered protection can be a crucial help 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," Makela said.

Moreover, the nasal spray can protect those people from serious diseases who do not gain sufficient immunity from vaccines, such as immunocompromised individuals and elderly.

According to the researchers, the molecule could also work against future animal-borne close relatives of SARS-CoV-2, which are expected to be the cause of entirely new coronavirus pandemics.

"Since the region in the coronavirus' 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," Makela 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," she added.

The researchers noted the technology used in developing the molecule can also be applicable to the prevention of many other viral diseases, particularly influenza and other respiratory viruses.

The next stage could be to test the molecule in clinical trials, after which it could be made commercially available, they said.