Study Finds Merbecoviruses Subgroup May Be Close to Infecting Humans

A recent study published in Nature Communications has found that while most merbecoviruses, a group of coronaviruses related to MERS-CoV, do not currently pose a direct threat to people, a subgroup called HKU5 showed traits that could make it capable of infecting humans with only a minor mutation. Michael Letko, a virologist at Washington State University and senior author of the study, explained, “Merbecoviruses—and HKU5 viruses in particular—really hadn’t been looked at much, but our study shows how these viruses infect cells. What we also found is HKU5 viruses may be only a small step away from being able to spill over into humans.”

Merbecoviruses use a spike protein to bind to receptors and invade host cells. For the study, the researchers created virus-like particles with the spike protein to test their ability to infect cells. While most merbecoviruses could not infect human cells, HKU5 viruses were able to use the ACE2 receptor, which is also used by SARS-CoV-2, but currently only in bats.

The study also showed that mutations in the HKU5 spike protein might allow it to bind to ACE2 receptors in other species, including humans. Another recent study documented an HKU5 virus jumping from bats to minks, indicating the potential for cross-species transmission. 

“These viruses are so closely related to MERS, so we have to be concerned if they ever infect humans,” Letko said. “While there’s no evidence they’ve crossed into people yet, the potential is there—and that makes them worth watching.”

The team used AlphaFold 3, an artificial intelligence tool, to model how the HKU5 spike protein interacts with ACE2, providing insights into how the virus might mutate. Letko noted that these methods could help future research and the development of vaccines and treatments.