An Adorable Way to Study How Kids Get Each Other Sick

At the start of 2022, as the Omicron variant of the coronavirus blazed across the United States, Seema Lakdawala was in Pittsburgh, finalizing plans to open a brand-new day care. She had found the perfect facility and signed the stack of paperwork; she had assembled a hodgepodge of plushies, puzzles, and toys. It was the perfect setup, one that “I’ve been dreaming about for years,” Lakdawala, a virologist at Emory University, told me. She couldn’t help but swell with pride, later that spring, when she ushered in her establishment’s first attendees: five young ferrets—including one deliberately infected with the flu.

Over the next several months, Lakdawala and her colleagues watched several cohorts of ferrets ping-pong flu viruses back and forth as they romped and wrestled