IHere’s the news that public health experts are expecting, but it’s terrifying: Virus researchers have discovered a new coronavirus in bats that can cause problems for humans. The virus can infect human cells and is already able to bypass the immune protection of COVID-19 vaccines.
Reporting in magazine PLoS pathogensScientists led by Michael Letko, assistant professor at Washington State University’s Paul Allen School of Public Health, found a group of coronaviruses similar to SARS-CoV-2 that was initially discovered living in bats in Russia in 2020. At the time, no Scientists believe that the virus called Khosta-2 poses a threat to people.
But when Letko’s team performed a more precise analysis, they found that the virus could infect human cells in the lab, the first warning sign that it could become a potential public health threat. A related virus was also found in Russian bats, Khosta-1, which could not easily enter human cells, but Khosta-2 was. Khosta-2 binds to the same protein, ACE2, that SARS-CoV-2 uses to penetrate human cells. “Receptors on human cells are the way viruses get into cells,” Letko says. “If the virus cannot enter the door, it cannot enter the cell, and it is difficult to detect any kind of infection.”
Khosta-2 does not appear to have this problem, because it appears to infect human cells easily. Even more alarming, when Letko collected serum from 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 an Omicron infection.
“We don’t want to scare anyone and say this is a completely vaccine-resistant virus,” Letko says. “But it is worrying that there are viruses that circulate in nature and have these properties – they can bind to human receptors and not be neutralized by current vaccine responses.”
The good news is that Letco’s studies show that, like the Omicron variant of SARS-CoV-2, Khosta-2 does not appear to contain genes that might indicate it can cause serious illness in people. But that could change if Khosta-2 starts spreading more widely and mixing genes from SARS-CoV-2. “One of the things we are concerned about is that when the relevant coronaviruses get into the same animal, and in the same cells, then they can recombine and bring out a new virus,” Letko says. “The concern is that SARS-CoV-2 could pass back into animals infected with something like Khosta-2 and recombine and then infect human cells. It could be resistant to vaccine immunity and also have some more virulent agents. What are the chances of that, who knows.” But it could theoretically happen during a recombination event.”
It’s a sobering reminder that pathogens are ready and waiting to jump from any 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 to them. “These viruses are really ubiquitous, and they will continue to be a problem for humans in general,” Letko says.
The findings come as the World Health Organization’s ACT – Council on Tracking and Accelerating Progress – represents the WHO’s working group Report That the ongoing response to the COVID-19 pandemic, in the form of tests, vaccines, and treatments, is slowing. With global immunity to the current SARS-CoV-2 reduced, fighting any new pathogens, including new coronaviruses such as Khosta-2, will become more difficult. According to the latest data collected by the World Health Organization, a quarter of people around the world still have not received an initial series of the COVID-19 vaccine.
Ultimately, having deeper files on the microbial world, especially information on how well some viruses can infect human cells, for example, will be important to making the response to public health threats more efficient and robust. Letko is building a database that includes information on the receptors for human viruses that they use to infect cells, and whether those viruses can evade existing vaccines. That way, he says, when new microbes similar to those in the database are discovered, researchers can have a head start in understanding how to control them. “At some point in the future, as these outbreaks continue, we won’t have to scramble whenever a new virus passes into humans,” he says. We can plug the virus into the database, and understand that it’s probably using these receptors to get to human cells, and it may be resistant to these types of vaccines or treatments. It’s a 10-20 year goal, but it’s possible. It’s not just a distant dream.”
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