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.

It was unclear the extent to which the agency has collected new intelligence on COVID-19's origins and whether that new evidence was used to formulate the latest assessment.

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