Two U.S. intelligence agencies reportedly support the lab leak theory — with low-to-moderate confidence. No evidence has been shared. Scientists have strong evidence of animal spillover at a market.

Policymakers have long grappled with how to handle experiments that might generate potentially dangerous viruses. Now, officials are considering whether oversight needs to be expanded.

In the wake of heated debate over the unproven lab leak theory, the world is calling on China to cooperate with investigations. But efforts to delve into this matter seem to be stalling.