In just eight months, Yan went from being a postdoctoral felow in virology and immunology at the Center for Infectious Disease Research at the University of Hong Kong's School of Public Health to being hailed as a hero by Trump's top advisers and conservative pundits. As early as mid-January 2019, Yan Limeng, researcher in Hong Kong, had heard rumors that a dangerous new virus had emerged in mainland China and that the government was playing it down. Ms. Yan feeds Wang Dinggang, the host of her favorite Chinese-language YouTube show.