The problem for the lab-leak position is that the U.S. has never had access to the Wuhan lab and has thus been unable to reach a definitive answer for more than five years. Now that the CIA has at last come to a conclusion, not all scientists are sold on what it has reported, seeing the results as thinly scientifically sourced.

The nuanced finding suggests the agency believes the totality of evidence makes a lab origin more likely than a natural origin.

China on Monday dismissed the possibility that the virus that caused COVID-19 leaked from a lab, after the CIA said it now favors the so-called lab leak theory over natural transmission. “It is extremely unlikely the pandemic was caused by a lab leak,