China at the end of December 2019."The Chinese government refused to let overseas experts, including ones in Hong Kong to do research in China," she said.Yan said very soon she and her colleagues across China discussed the peculiar virus but that she soon noted a sharp shift in tone.
Doctors and researchers who had been openly discussing the virus suddenly clammed up. Those from the city of Wuhan--which later would become the hub of the outbreak -- went silent and others were warned not to ask them details.The doctors said, ominously, "We cannot talk about it, but we need to wear masks,'" Yan said.
The numbers of human-to-human transmission cases then began to grow exponentially, according to her sources.Yan made the decision to leave.