NPR Bird flu has ripped through the animal kingdom for the past few years now, killing countless birds and crossing into an alarming number of mammals.
Yet people remain largely untouched.
Even though the official tally of human cases in the U.S. is most certainly an undercount, there’s still no evidence this strain of H5N1 has spread widely among us. But if the virus gains certain mutations, scientists fear it could trigger another pandemic.
This prospect has propelled research into whether our defenses built up from past flu seasons can offer any protection against H5N1 bird flu.