PULLMAN, Wash. — Is the next pandemic on the horizon? Scientists are warning of a new, COVID-like virus called Khosta-2 originating from a Russian bat. It is believed to be capable of infecting humans, and would be resistant to current vaccines.
Khosta-2 was found two years ago in horsehoe bats. Its discovery adds to evidence that sarbecoviruses — part of the coronavirus family — are rife across Asia and eastern Europe.
“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,” says study lead author Dr Michael Letko, of Washington State University, in a statement.
Past studies suggest that SARS-CoV-2, the virus that causes COVID-19, emerged in an animal, most likely a bat, before spreading to humans. The precise origins of the virus are unknown and have been investigated by a team commissioned by the World Health Organization (WHO).
What will bring about the next pandemic?
Scientists believe another pandemic will happen during our lifetime. Coronaviruses can move between different mammals such as cats, dogs and minks. By moving between species, the virus can mutate and evolve into a new pathogen, which could explain how COVID-19 emerged.
In the latest research, Dr Letko and colleagues found spike proteins from Khosta-2 can infect human cells. It is resistant to both the monoclonal antibodies and serum from individuals vaccinated against COVID-19.
Both Khosta-2 and SARS-CoV-2 belong to the same sub-category of coronaviruses known as sarbecoviruses. The study highlights the need to develop universal vaccines to protect against sarbecoviruses in general, rather than just against known variants of SARS-CoV-2.
“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,” says Dr. Letko. “But that is a list that’s ever changing. We need to broaden the design of these vaccines to protect against all sarbecoviruses.”
Hundreds of sarbecoviruses have been discovered in recent years, mainly in bats in Asia. 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 they were not a threat to humans.
“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,” explains Letko. “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.”
Khosta-2 vs. COVID-19
The study, published in the journal PLoS pathogens, finds that Khosta-1 poses a low risk to humans. Khosta-2, however, demonstrates “troubling traits.” Like SARS-CoV-2, it uses its spike protein to infect cells by attaching to a receptor protein, called ACE2 (angiotensin converting enzyme 2) found throughout human cells.
Using serum derived from human populations vaccinated for COVID, scientists also saw Khosta-2 was not neutralized. Further tests found the antibodies were also ineffective against serum from people infected with the omicron variant.
The new virus lacks some genes involved in causing COVID in humans. But there is a risk of recombining it with a second virus like SARS-CoV-2.
“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,” says Letko.
South West News Service writer Mark Waghorn contributed to this report.
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