In this harrowing, incredibly reported story co-published by Science and Retraction Watch, Brendan Borrell uncovers how “Mei,” a 6-year-old girl in China, died a week after an experimental gene-editing trial went wrong—and how her medical team, led by neuroscientist Zilong Qiu, downplayed the risks to her parents, did not publicly disclose her death, and has faced no real accountability.

On 23 March 2025, the day before the procedure, the family settled into a shared room inside a crowded pediatric ward. When the other girl in the room broke into tears, Mei handed her one of her favorite stuffed animals: a blue bird. “She liked to give things to other kids,” Jason said.

The next day Mei put on a brave face as she was taken to the procedure room. Yu’s handpicked doctor inserted a needle between two vertebrae on her lower back and withdrew just over a teaspoon of spinal fluid to create space for the drug. Then, he swapped syringes and gently pressed down on the plunger, filling her spinal canal with viruses.