Tuesday marked the fifth anniversary of the World Health Organization declaring Covid-19 a global pandemic. For science writer Carl Zimmer, a columnist for the New York Times, covering Covid meant “watching [scientists] figuring out this disease in real time.” Notably, “there were a lot of mysteries about it. I was really struck as, as others were, by how strange it was that, that the just a fundamental question of how Covid spread was so unclear and was leading to so much argument,” he said.

Intrigued by both the public and scientific confusion over airborne infection, he began examining history. Eventually, he realized, “I’m writing about life in the air, and it turns out to have this incredible history that goes back many centuries and involves all sorts of people.”

That led to his latest book, “Air-Borne: The Hidden History of the Life We Breathe,” which he discussed with guest host and STAT science writer Megan Molteni on this episode of the “First Opinion Podcast,” which is back for a new season.