IThis is the news that public health experts have been waiting for but dreading: virus-hunting researchers have discovered a new coronavirus in bats that could cause problems for the human population. The virus can infect human cells and is already able to bypass the immune protection of COVID-19 vaccines.
Report in the log PLoS Pathogensscientists led by Michael Letko, assistant professor at Washington State University’s Paul Allen School of Public Health, have discovered a cluster of coronaviruses similar to SARS-CoV-2 that were originally found living in bats -mice in Russia in 2020. At the time, scientists did not believe the virus, called Khosta-2, posed a threat to humans.
But when Letko’s team performed further analysis, they found the virus could infect human cells in the lab, the first warning sign that it could become a possible public health threat. A related virus also found in Russian bats, Khosta-1, could not easily enter human cells, but Khosta-2 could. Khosta-2 attaches to the same protein, ACE2, that SARS-CoV-2 uses to enter human cells. “Receptors on human cells are the pathway by which viruses enter cells,” Letko explains. “If a virus can’t get into the door, it can’t get into the cell, and it’s hard to establish any kind of infection.”
Khosta-2 doesn’t seem to have this problem, as it seems to easily infect human cells. Even more troubling, when Letko combined the serum of people vaccinated against COVID-19 with Khosta-2, the antibodies in the serum did not neutralize the virus. The same thing happened when they combined the Khosta-2 virus with serum from people who had recovered from Omicron infections.
“We don’t want to scare anyone into saying this is a completely vaccine-resistant virus,” Letko says. “But it is concerning that there are viruses circulating in nature that have these properties – they can bind to human receptors and are not so neutralized by current vaccine responses.”
The good news is that Letko’s studies show that, like the Omicron variant of SARS-CoV-2, Khosta-2 does not appear to have genes that would suggest it could cause serious disease in humans. But that could change if Khosta-2 starts circulating more widely and mixing with genes from SARS-CoV-2. “One of the things that worries us is that when related coronaviruses enter the same animal and the same cells, they can then recombine and produce a new virus,” says Letko. “The concern is that SARS-CoV-2 could spread to animals infected with something like Khosta-2 and recombine and then infect human cells. They could be resistant to vaccine immunity and also have more virulent factors. What are the chances of that happening, who knows. But it could in theory happen during a recombination event.
It is a sobering reminder that pathogens are ready and waiting to jump from a number of animal species to humans. And in many cases, as with SARS-CoV-2, these microbes will be new to humans and therefore encounter little resistance in the form of immunity against them. “These viruses are really prevalent everywhere and will continue to be a problem for humans in general,” Letko says.
The findings are published by the World Health Organization (WHO) Accelerator’s Council Tracking and Accelerating Progress (ACT) working group. report that the continued response to the COVID-19 pandemic, in the form of tests, vaccinations and treatments, has stalled. With lower global immunity to the current SARS-CoV-2 virus, the fight against any new pathogens, including novel coronaviruses like Khosta-2, would become more difficult. According to the latest data collected by WHO, a quarter of people worldwide have still not received a primary vaccination against COVID-19.
Ultimately, having deeper records of the microbial world, including information on the ability of certain viruses to infect human cells, for example, will be important in making the response to public health threats more efficient and powerful. Letko is working to build a database that includes information about the human receptors that viruses use to infect cells, and whether or not those viruses can evade existing vaccines. That way, he says, when new microbes similar to those in the database are discovered, researchers could have a head start in figuring out how to control them. “At some point in the future, as these outbreaks continue, we won’t have to rush every time a new virus rushes into people,” he says. “We could plug the virus into the database and figure out that it probably uses these receptors to enter human cells and that it could be resistant to these types of vaccines or treatments. It’s a 10 to 20 year goal, but it’s possible. It’s not just a chimera. »
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