A new study published in Science has revealed that a single mutation in the H5N1 bird flu virus could significantly enhance its ability to infect human cells, raising concerns over a potential human pandemic.
The study identifies a mutation called Q226L in the virus’s hemagglutinin protein, which improves the virus’s binding to human cell receptors. While this mutation has been observed in laboratory settings, it has not yet occurred in real-world cases.
“This is the red flag that says we really need to keep paying attention to what’s going on,” said James Paulson, co-senior author of the study.
The H5N1 strain has caused 58 human infections across seven U.S. states in 2024, with California reporting the most cases. Most human infections stem from direct contact with contaminated environments, infected birds, or dairy cows, with 707 dairy herds affected this year.
Scientists emphasized that while the virus’s mutation potential is concerning, the current strain is not transmissible between humans. “Our study doesn’t suggest such evolution has occurred,” said Ting-Hui Lin, lead author.
Experts are urging increased surveillance, particularly as the upcoming flu season could heighten the risk of a hybrid virus emerging in farm workers exposed to both human and avian influenza.