Could the Bird Flu Become Airborne?

Scientists were slow to recognize that Covid spreads through the air. Some are now trying to get ahead of the bird flu.

In early February 2020, China locked down more than 50 million people, hoping to hinder the spread of a new coronavirus. No one knew at the time exactly how it was spreading, but Lidia Morawska, an expert on air quality at Queensland University of Technology in Australia, did not like the clues she managed to find.

It looked to her as if the coronavirus was spreading through the air, ferried by wafting droplets exhaled by the infected. If that were true, then standard measures such as disinfecting surfaces and staying a few feet away from people with symptoms would not be enough to avoid infection.

Dr. Morawska and her colleague, Junji Cao at the Chinese Academy of Sciences in Beijing, drafted a dire warning. Ignoring the airborne spread of the virus, they wrote, would lead to many more infections. But when the scientists sent their commentary to medical journals, they were rejected over and over again.

“No one would listen,” Dr. Morawska said.

It took more than two years for the World Health Organization to officially acknowledge that Covid spread through the air. Now, five years after Dr. Morawska started sounding the alarm, scientists are paying more attention to how other diseases may also spread through the air. At the top of their list is the bird flu.

Last year, the Centers for Disease Control recorded 66 people in the United States who were infected by a strain of avian influenza called H5N1. Some of them most likely got sick by handling virus-laden birds. In March, the Department of Agriculture discovered cows that were also infected with H5N1, and that the animals could pass the virus to people — possibly through droplets splashed from milking machinery.