EXPLAINER: The US investigation into COVID-19 origins

Once dismissed by most public health experts and government officials, the hypothesis that COVID-19 leaked from a Chinese lab is now receiving scrutiny under a new U.S. investigation

WASHINGTON -- Once dismissed by most public health experts and government officials, the hypothesis that COVID-19 leaked accidentally from a Chinese lab is now receiving scrutiny under a new U.S. investigation. Experts say the 90-day review ordered on May 26 by President Joe Biden will push American intelligence agencies to collect more information and review what they already have. Former State Department officials under President Donald Trump have publicly pushed for further investigation into virus origins, as have scientists and the World Health Organization. Many scientists, including Dr. Anthony Fauci, say they still believe the virus most likely occurred in nature and jumped from animals to humans. Virus researchers have not publicly identified any key new scientific evidence that might make the lab-leak hypothesis more likely. Virologists also say it is unlikely that any definitive answer about virus origins will be possible in 90 days. The work to fully confirm origins and pathways of past viruses — such as the first SARS or HIV/AIDS — has taken years or decades.