IThis isn’t the news public health experts expected, but it’s scary: virus-hunting researchers have discovered a new coronavirus in bats that could cause trouble for people. The virus can infect human cells and has been able to provide immune protection from the COVID-19 vaccine.
Report in magazine Pathogen PLoSScientists led by Michael Letko, an assistant professor at the Paul Allen School of Public Health at Washington State University, have found a group of coronaviruses similar to SARS-CoV-2 that was originally discovered to live in bats. in Russia in 2020. At the time, scientists did not think that the virus called Khosta-2 posed a threat to humans.
But when Letko’s team took a closer look, they discovered that the virus could infect human cells in the lab, the first warning sign that it could become a public health threat. A related virus also found in Russian bats, Khosta-1, cannot enter human cells easily, but Khosta-2 can. Khosta-2 attaches to the same protein, ACE2, that SARS-CoV-2 uses to enter human cells. “The receptors on human cells are the way the virus enters the cell,” said Letko. “If the virus can’t get in the door, it can’t get into the cell and it’s very difficult to establish any kind of infection.”
Khosta-2 doesn’t seem to have that problem, as it seems to easily infect human cells. To make matters worse, when Letko combined the serum of people who had been vaccinated against COVID-19 with Khosta-2, the antibodies in the serum failed to neutralize the virus. The same thing happened when they combined the Khosta-2 virus with the serum of people who had recovered from the Omicron infection.
“We don’t want to scare anyone and say this is a completely vaccine-resistant virus,” said Letko. “But the concern is that there are viruses circulating in the wild that have these properties — they can bind to human receptors and not be neutralized by current vaccine reactions.” .
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 the genes that suggest it can cause serious illness in humans. But that could change if Khosta-2 begins to circulate more widely and mix 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, they can recombine and create a new virus,” said Letko. “The worry is that SARS-CoV-2 could spill back into animals infected with something like Khosta-2 and recombine and infect human cells. They may be resistant to vaccine immunity and also have some more virulence factors. What are the chances of that, who knows. But in theory it could happen in a recombination event.”
It’s a stark reminder that pathogens are ready and waiting to jump from any animal to humans. And in many cases, as with SARS-CoV-2, these bacteria will be very new to humans and therefore less likely to encounter resistance in the form of immunity against them. “These viruses are really ubiquitous and will continue to be a problem for humans in general,” said Letko.
The findings are presented in the World Health Organization (WHO) ACT – Accelerator Council’s Monitoring and Acceleration Working Group – report The continued response to the COVID-19 pandemic, in the form of testing, vaccination and treatment, is stalling. With lower global immunity to the current SARS-CoV-2 virus, it will become more difficult to fight off any new pathogens, including novel coronaviruses like Khosta-2. According to the latest data collected by WHO, a quarter of people in the world are still unvaccinated against the main wave of COVID-19.
Ultimately, it will be important to have deeper profiles of the microbial world, especially information on how well certain viruses can infect human cells, for example. to make the response to public health threats more effective and robust. Letko is working on building a database that includes information on which viruses use human receptors to infect cells and whether those viruses can evade existing vaccines. are not. That way, he said, when new bacteria are discovered that are similar to those in the database, researchers can begin to learn how to control them. “At some point in the future, as these outbreaks continue, we won’t have to scramble whenever a new virus infects people,” he said. “We can put the virus in the database and understand that it can use these receptors to get into human cells and possibly become resistant to these vaccines or treatments. That’s a 10 to 20 year goal, but it’s entirely possible. It’s not just a pipe dream.”
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