Saturday, December 9

Newly discovered covid-like virus could infect humans

Vials containing one of the vaccines against covid-19. / r. garrido / reuters

It comes from bats, has been located in Russia and, according to scientists who have studied it, if it were to spread it would be resistant to current vaccines


A recently discovered virus in a Russian bat that is similar to SARS-CoV-2 is likely capable of infecting humans and, if it were to spread, is resistant to current vaccines, researchers report in the journal PLoS Pathogens. ‘.

Led by scientists at Washington State University’s Paul G. Allen School of Global Health, this team discovered that proteins from the bat virus, called Khosta-2, can infect human cells. They also found that they are resistant to both monoclonal antibodies and serum from people vaccinated against SARS-CoV-2. Both Khosta-2 and SARS-CoV-2 belong to the same subcategory of coronaviruses known as sarbecoviruses.

“Our research further demonstrates that sarbecoviruses circulating in wildlife outside of Asia – including in places like western Russia, where the Khosta-2 virus was found – also pose a threat to global health and vaccination campaigns in Europe. course against SARS-CoV-2,” says Michael Letko, a virologist at WSU and corresponding author of the study.

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Letko maintains that the discovery of Khosta-2 highlights the need to develop universal vaccines that protect against sarbecoviruses in general, and not only against the known variants of SARS-CoV-2.

“Right now, there are groups trying to come up with a vaccine that not only protects against the next variant of SARS-2, but also protects us against sarbecoviruses in general,” Letko said. Unfortunately, many of our current vaccines are designed for specific viruses that we know infect human cells or those that seem to pose the greatest risk of infecting us. But that’s a constantly changing list. We need to scale up the design of these vaccines to protect against all sarbecoviruses,” she says.

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other discoveries

Although hundreds of sarbecoviruses have been discovered in recent years, mostly in Asian bats, most are not capable of infecting human cells. The Khosta-1 and Khosta-2 viruses were discovered in Russian bats in late 2020, and it initially appeared that they were not a threat to humans.

“Genetically, these strange Russian viruses resembled others that had been discovered in other parts of the world, but since they did not resemble SARS-CoV-2, no one thought they were really anything to get too excited about,” Letko said. But when we studied them further, we were very surprised to discover that they could infect human cells. That changes our understanding of these viruses a bit, where they come from and which regions are of concern.”

Letko teamed up with a pair of WSU professors, viral ecologist Stephanie Seifert and viral immunologist Bonnie Gunn, to study the two newly discovered viruses. They determined that Khosta-1 posed a low risk to humans, but Khosta-2 exhibited some worrying traits.

The team found that, like SARS-CoV-2, Khosta-2 can use its spike protein to infect cells by binding to a receptor protein, called angiotensin-converting enzyme 2 (ACE2), found on all human cells. They then set out to determine whether current vaccines protect against the new virus.

Using serum from human populations vaccinated against covid-19, the team found that Khosta-2 was not neutralized by current vaccines. They also tested serum from people infected with the omicron variant, but the antibodies were also ineffective.

A hope

Fortunately, Letko points out that the new virus lacks some of the genes thought to be involved in pathogenesis in humans. However, there is a risk that Khosta-2 could recombine with a second virus such as SARS-CoV-2.

“When we see that SARS-2 has this ability to spread from humans to wildlife, and then there are other viruses like Khosta-2 waiting in those animals with these properties that we really don’t want them to have, it sets this scenario in the one where you keep rolling the dice until they combine to make a potentially riskier virus,” says Letko.

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