The World Health Organization is set to publish a report on its work tracing the origins of the pandemic. A team visited Wuhan last month and said it was "extremely unlikely" that the virus leaked from a lab there. Wu Zhiwei, a public health expert from the Medical School of Nanjing University, shared his insights with CGTN. He said it is possible that the virus emerged in the population earlier than was initially thought in a low-frequency manner. He said geopolitical issues remain the number one challenge for health experts investigating the virus's origin.