In their Research Article “A single mutation in bovine influenza H5N1 hemagglutinin switches specificity to human receptors” (6 December 2024, p. 1128), T.-H. Lin et al. find that a mutation from glutamine to leucine at the 226 residue in the hemagglutinin protein of the H5N1 influenza virus leads to human receptor specificity, consistent with other work showing that the new H5N1 avian and bovine influenza virus variants exhibit altered receptor binding preferences (1, 2). Traditionally associated with avianspecific α-2,3–linked sialic acid receptors, emerging H5N1 strains display a growing ability to bind humanlike α-2,6–linked sialic acid receptors (3, 4), increasing the risk of human infection. In their Research Article “A single mutation in bovine influenza H5N1 hemagglutinin switches specificity to human receptors” (6 December 2024, p. 1128), T.-H. Lin et al. find that a mutation from glutamine to leucine at the 226 residue in the hemagglutinin protein of the H5N1 influenza virus leads to human receptor specificity, consistent with other work showing that the new H5N1 avian and bovine influenza virus variants exhibit altered receptor binding preferences (1, 2). Traditionally associated with avianspecific α-2,3–linked sialic acid receptors, emerging H5N1 strains display a growing ability to bind humanlike α-2,6–linked sialic acid receptors (3, 4), increasing the risk of human infection. Science