Western officials, researchers cast doubt on China lab virus leak theory

"We listened again and again to numerous scientists who looked at the sequences and looked at this virus. And we are assured that this virus is natural in origin," said Mike Ryan, executive director of the WHO Health Emergencies Programme, during a virtual news conference.

Ryan emphasized the importance of better understanding the virus and understanding the animal-human interface and how the barrier between them was breached.

"The purpose of understanding that is that we can put in place the necessary prevention and public health measures to prevent that happening again anywhere," he said.