A new strain of coronavirus discovered in China, known as HKU5-CoV-2, could be only a few mutations away from triggering the next deadly pandemic, say American scientists. The virus was identified by researchers at Washington State University (WSU). The researchers have said that it shares close genetic similarities with Middle East Respiratory Syndrome (MERS)—a highly lethal virus that kills nearly a third of those it infects. The findings have raised serious concern in the global scientific community.A Close Cousin of MERSMERS, which emerged in 2012 and has caused sporadic outbreaks primarily in the Arabian Peninsula, is known for its severe respiratory symptoms and high mortality rate. HKU5-CoV-2, the new virus under scrutiny, belongs to the merbecovirus family—a group of viruses that includes MERS. While not yet known to infect humans, scientists warn that a minor genetic mutation could allow it to do so, raising the possibility of another global health emergency similar to COVID-19.“This virus may be only a small step away from being able to spill over into humans,” said Professor Michael Letko, a virologist at WSU and co-lead author of the study.What the Study FoundThe study focused on how HKU5-CoV-2 interacts with human cells. Originally found in bats, this virus was identified by Chinese scientists from the same lab some speculate may have been linked to the origins of COVID-19. In the new study, WSU researchers examined the virus's ability to bind to human ACE2 receptors—proteins located in the nose, mouth, and throat that serve as entry points for coronaviruses.Using advanced cryo-electron microscopy, researchers captured detailed images of the virus's spike protein, revealing that key segments of the spike often remain “closed.” This closed structure typically makes infection harder—but not impossible.The team observed that while human cells generally resist infection from HKU5-CoV-2, the virus could latch onto human ACE2 receptors if specific mutations occur. These mutations could enable the virus to enter human cells more effectively, increasing its potential to cause disease.Risks from Intermediate Animal HostsAnother concern is the possibility of the virus mutating in intermediate animal hosts, such as mink or civets, before jumping to humans. Such transmission chains have been seen in other coronavirus outbreaks, including both SARS and MERS. If HKU5-CoV-2 were to infect these animals, it might gain the ability to infect humans more efficiently, scientists warn.“Viruses that are already this close to MERS in structure and function are definitely worth monitoring,” Letko emphasized.Lineage 2 and Immediate ThreatsEarlier in 2025, researchers in Wuhan reported that one strain of HKU5—Lineage 2—already shows the ability to bind to human ACE2 receptors without further mutation. This suggests that some forms of the virus may already be equipped to infect humans.Building on that discovery, the WSU team expanded their research to look at the entire merbecovirus family. Their findings indicate that several other strains, not just Lineage 2, may only require minimal changes to become capable of infecting humans.Vigilance NeededAs the world continues to recover from the COVID-19 pandemic, scientists stress the importance of ongoing surveillance and pre-emptive research into emerging viruses like HKU5-CoV-2. Even if they cannot yet infect humans, understanding their structure and behavior is crucial for early intervention."The lesson from COVID-19 is clear—we cannot afford to ignore even small viral threats," Letko concluded.