Top Chinese officials secretly determined they were likely facing a pandemic from a new coronavirus in mid-January, ordering preparations even as they downplayed it in public.
Internal documents obtained by the AP show that because warnings were muffled inside China, it took a confirmed case in Thailand to jolt Beijing into recognizing the possible pandemic before them.
Still, it was nearly a week before officials warned the public.
In that week, tens of thousands dined at a mass banquet and millions traveled through Wuhan, at the center of the outbreak.
Experts say an earlier warning could have saved lives.