Virus-hunting researchers have discovered a new coronavirus in bats identified to be resistant to vaccines—a finding that could spell trouble for the human population.
Public health experts anticipated this finding and noted that the virus can infect human cells and is already able to skirt the immune protection from COVID-19 vaccines.
According to the journal PLOS Pathogens, scientists led by Michael Letko, an assistant professor in the Paul Allen School of Public Health at Washington State University, found a group of coronaviruses similar to SARS-CoV-2.
The new viruses were initially discovered in bats in Russia in 2020, but, during that time, scientists did not think the virus, called Khosta-2, posed a threat to people.
New coronavirus in bats could infect humans
After a more careful analysis conducted by Letko’s team of scientists, it was found that the virus in bats could infect human cells in the lab. This was the first sign that it could become a possible public health threat.
However, a related virus, Khosta-1, also found in the Russian bats, could not readily be transmitted to human cells while Khosta-2 could, as it attaches to the same protein, ACE2, that SARS-CoV-2 uses to penetrate human cells.
Letko said, “Receptors on human cells are the way that viruses get into cells. If a virus can’t get in the door, then it can’t get into the cell, and it’s difficult to establish any type of infection.”
Khosta-2 doesn’t appear to have that problem since it seems to infect human cells readily.
When Letko combined serum from people who have been vaccinated against COVID-19 with Khosta-2, the antibodies in the serum did not neutralize the virus, a finding that is even more troubling.
When they combined the Khosta-2 virus with serum from people who had recovered from Omicron infections, the results were replicated.
“We don’t want to scare anybody and say 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,” he added.
Khosta-2 virus seems not to have genes causing serious disease in people
The study by Letko’s team shows that much like the Omicron variant of SARS-CoV-2, Khosta-2 does not seem to have genes that would suggest it could cause serious disease in people. This is a positive finding.
However, that could change if Khosta-2 starts circulating more widely and mixing with genes from SARS-CoV-2.
“One of the things we’re worried about is that when related coronaviruses get into the same animal and into the same cells, then they can recombine and out comes a new virus,” says Letko.
“The worry is that SARS-CoV-2 could spill back over to animals infected with something like Khosta-2 and recombine and then infect human cells,” Letko explained. “They could be resistant to vaccine-immunity and also have some more virulent factors…[though] what the chances of that are, who knows.”
In theory, this could happen during recombination, a sobering reminder that pathogens are ready and waiting to jump from any number of animal species into humans.
In many cases, as with SARS-CoV-2, these microbes will be new to people and therefore encounter little resistance in the form of immunity against them.
“These viruses are really widespread everywhere, and are going to continue to be an issue for humans in general,” says Letko.
Response to coronavirus guidelines stalling
The new discovery comes as the World Health Organization’s (WHO) ACT—Accelerator’s Council Tracking and Accelerating Progress—working group reports that continued response to the COVID-19 pandemic, in the form of testing, vaccinations, and treatments, is stalling.
Combating any new pathogens including new coronaviruses like Khosta-2 would become more difficult given the lower global immunity to the current SARS-CoV-2 virus.
According to the latest data collected by the WHO, a quarter of people around the world still have not received a primary series of COVID-19 vaccination.
Ultimately, having deeper dossiers on the microbial world, especially information on how well certain viruses can infect human cells, for example, will be important in the efficient and productive response to public health threats.
Letko is working on building a database that includes information on which human receptors viruses use to infect cells and whether or not those viruses can evade existing vaccines.
That way, Letko says, when new microbes are discovered that are similar to those in the database, researchers might have a head start on 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 spills over into people,” he says.
“We could plug the virus into the database, and understand that it probably uses these receptors to get into human cells, and might be resistant to these types of vaccines or treatments,” he theorized. “It’s a [ten to twenty] year goal, but it’s possible. It’s not just a pipe dream.”