A man in Chile is infected with a bird flu that has concerning mutations, but the threat to people from the virus remains low, U.S. health officials said Friday.
Past animal studies suggest these mutations could cause the virus to be more harmful or spread more easily, health officials said. But they also said there is no evidence that the mutations would make it easier for it to take root in a person’s upper lungs — a development that would raise concerns about spread among people.
