A report on the origins of Covid-19 by a U.S. government national laboratory concluded that the hypothesis of a virus leak from a Chinese lab in Wuhan is plausible and deserves further investigation, The Wall Street Journal said on Monday, citing people familiar with the classified document.
The study was prepared in May 2020 by the Lawrence Livermore National Laboratory in California and was referred to by the State Department when it conducted an inquiry into the pandemic's origins during the final months of the Trump administration, the WSJ report said.
Lawrence Livermore's assessment drew on a genomic analysis of the Covid-19 virus, the Journal said. Lawrence Livermore declined to comment on The Wall Street Journal report.
President Joe Biden said last month he had ordered aides to find answers to the origin of the virus.
U.S. intelligence agencies are considering two likely scenarios - that the virus resulted from a laboratory accident or that it emerged from human contact with an infected animal - but they have not come to a conclusion, Biden said.
A still-classified U.S. intelligence report circulated during former President Donald Trump's administration alleged that three researchers at China's Wuhan Institute of Virology became so ill in November 2019 that they sought hospital care, U.S. government sources have said.
U.S. officials have accused China of not being transparent about the virus' origins, a charge Beijing has denied.
Separately, Mike Ryan, a top World Health Organization official said on Monday the WHO cannot compel China to divulge more data on Covid-19's origins, while adding it will propose studies needed to take understanding of where the virus emerged to the "next level."
Earlier this month, U.S. infectious disease expert Dr. Anthony Fauci called on China to release the medical records of nine people whose ailments might provide vital clues into whether Covid-19 first emerged as the result of a lab leak.