China is preparing to examine 200 thousand blood samples taken in the city of Wuhan until the last months of 2019, before the Covid epidemic exploded, to try to shed light on how and when SarsCov2 spillovered passing from the animal to the 'man.

To give the news exclusively, citing a Chinese official, is the CNN. The analyzes had been requested since last February by the WHO.

The samples in question were stored for two years in the Wuham blood center, in case they were needed as evidence in any legal action related to their donation.

That period will expire soon, hence the need to start the tests, the preparation of which is currently underway, the Chinese official told CNN.

The samples contain "absolutely vital clues," said Maureen Miller, associate professor of epidemiology at Columbia University, urging Beijing to allow foreign experts to witness the trial.

"Nobody will believe the results that China reports unless there are qualified observers," he said.

The head of the Chinese team working on the WHO investigation, Liang Wannian, explained in a press conference as early as July that Beijing would test the samples, adding that once obtained, "the results would be handed over to Chinese and foreign experts" , while the pool of experts had ongoing evaluations "on the test methods and the action plan to be implemented after" the two years.

If stored properly, the samples could contain crucial elements of the first human-made antibodies to the disease.

Liang pointed out that while the first reported case in Wuhan was from December 8, 2019, "our research and previous related documents by Chinese scientists fully suggest that December 8 is not likely to have been the main case. There may be others that are the case. are verified first ".

Joe Biden's administration attacked Beijing, noting that "Chinese officials have worked to prevent international investigators from accessing crucial information on the origins of the pandemic." The US intelligence investigation concluded that both natural animal-to-human transmission and laboratory escape are two plausible theories.