A newly discovered Covid virus found in Russian bats is feared to be capable of infecting humans - and is currently resistant to all known existing vaccines.
A team of researchers discovered proteins from a bat virus known as Khosta-2 can migrate to human cells.
Unlike known Covid infections, it is resistant to antibodies and serums populations are currently protected against.
Study author Michael Letko has called for universal vaccines to be developed to help protect against other dangerous viruses found in the wild.
Mr Letko, a virologist from Washington State University's Paul G. Allen School for Global Health, said: “Our research further demonstrates that sarbecoviruses circulating in wildlife outside of 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.
“Genetically, these weird Russian viruses looked like some of the others that had been discovered elsewhere around the world, but because they did not look like SARS-CoV-2, no one thought they were really anything to get too excited about.
"But when we looked at them more, we were really surprised to find they could infect human cells. That changes a little bit of our understanding of these viruses, where they come from and what regions are concerning."
Scientists have found hundreds of the sarbecoviruses in recent years, with the majority discovered in Asia.
Khosta-1 and Khosta-2 viruses were discovered in Russian bats in 2020 and initial tests found they posed no threat to humans.
The team from WSU found Khosta-2 can use its spike protein to infect cells by attaching to a receptor protein.
Tests later showed Khosta-2 was not neutralised by current vaccines.
Antibodies from people infected with omicron were also found to be ineffective.
Letko added: “When you see SARS-2 has this ability to spill back from humans and into wildlife, and then there are other viruses like Khosta-2 waiting in those animals with these properties we really don’t want them to have, it sets up this scenario where you keep rolling the dice until they combine to make a potentially riskier virus.
“Right now, there are groups trying to come up with a vaccine that doesn’t just protect against the next variant of SARS-2 but actually protects us against the sarbecoviruses in general
“Unfortunately, many of our current vaccines are designed to specific viruses we know infect human cells or those that seem to pose the biggest risk to infect us.
“But that is a list that’s ever changing. We need to broaden the design of these vaccines to protect against all sarbecoviruses.”
Earlier this year the number of people in the UK who have Covid-19 recorded on their death certificate since the pandemic began reached 200,000, according to the Office for National Statistics.
