The shift in the receptor-binding specificity of influenza A viruses is mostly determined by mutations in viral haemagglutinin. In this Review, Gao and colleagues discuss recent crystallographic studies that provide molecular insights into haemagglutinin–host receptor interactions that have enabled several influenza A virus subtypes to 'jump' from avian to human hosts.
- Yi Shi
- Ying Wu
- George F. Gao
