A virus recently discovered in a Russian bat is similar to the one causing the Covid-19 pandemic and can also infect humans, a new study finds.
Researchers, including those from Washington State University in the US, found that the spike proteins from the bat virus – called Khosta-2 – can infect human cells and that it is resistant to both antibodies and serum from individuals vaccinated for Sars-CoV -2.
They say that both Khosta-2 and the Covid virus belong to the same subcategory of coronavirus known as sarbecovirus.
“Our research further shows that sarbecoviruses circulating in wildlife outside Asia—even in places like western Russia where the Khosta-2 virus was found—also pose a threat to global health and ongoing vaccine campaigns against Sars-CoV-2,” the researchers wrote . in the study, published in the journal PLOS Pathogens on Thursday.
Researchers are calling for the development of universal vaccines to protect against sarbecoviruses in general, rather than just known variants of the Sars-CoV-2 virus.
“Unfortunately, many of our current vaccines are designed for specific viruses that we know infect human cells or those that appear to pose the greatest risk of infecting us. But it’s an ever-changing list. We need to expand the design of these the vaccines to protect against all sarbecoviruses,” study co-author Michael Letko said in a statement.
Scientists initially discovered the Khosta-1 and Khosta-2 viruses in Russian bats in late 2020, but thought they were not a threat to humans.
“But when we looked at them more, we were really surprised to find that they could infect human cells. It changes a little bit our understanding of these viruses, where they come from and which regions are involved,” said Dr Letko.
While Khosta-1 posed a low risk to humans, scientists say Khosta-2 showed some troubling properties.
They found that it can use its spike protein to infect cells by attaching to a receptor protein, called angiotensin-converting enzyme 2 (ACE2), found in human cells.
It is the same ACE2 protein that the Covid-19 virus uses as a gateway to enter and infect human cells.
When researchers assessed whether current anti-Covid vaccines can protect against the new virus using serum from human populations vaccinated for Covid-19, they saw that Khosta-2 was not neutralized.
Researchers also tested serum from people infected with the omicron variant against Khosta-2, but these antibodies were also ineffective.
While the new virus lacks some genes thought to be involved in its pathogenesis in humans, they say there is a risk of Khosta-2 recombining with another virus such as Sars-CoV-2.
“When you see that Sars-2 has this ability to spill back from humans into wildlife, and then there are other viruses like Khosta-2 that are waiting in those animals with these characteristics that we don’t really want them to have, puts it sets up this scenario where you keep rolling the dice until they combine to create a potentially more risky virus,” Dr Letko said.