Scientists weigh in on the spread of H5N1 and highlight clues that portend what might come next. Bird flu, or H5N1 avian influenza, has been circulating across North America since 2022, infecting birds, livestock, wildlife, pets, and humans. Despite 70 documented human cases, there are no known instances of human-to-human transmission — but some scientists are starting to worry that it’s only a matter of time.
Experts from the Harvard Medical School-led Massachusetts Consortium on Pathogen Readiness, or MassCPR, answered questions on March 5 about how H5N1 is spreading and evolving and discussed the state of surveillance efforts, testing, and vaccines. “I think we’re all wondering whether this is a minor blip or if we are facing what may turn into an existential threat,” said Bruce Walker, director of the Ragon Institute of Mass General, MIT, and Harvard and member of the MassCPR executive committee.