President Biden said Wednesday he had asked U.S. intelligence agencies to "redouble their efforts" to determine the origin of the coronavirus, an abrupt departure from the previous White House position of relying on the World Health Organization to uncover how the contagion started. The new message reflects a notable shift in some prominent scientists' assessments that the virus all but certainly jumped from an animal species to humans. The theory that has more recently gained traction is that the pandemic — which has killed more than 3.4 million people worldwide — may have accidentally escaped from the Wuhan Institute of Virology in China, though that is far from conclusive. Biden ordered intelligence officials to deliver a report within 90 days "that could bring us closer to a definitive conclusion." Timeline: How the Wuhan lab-leak theory suddenly became credible Some Republicans pushed the idea early on that the Wuhan lab, rather than a natural transmission from animals to humans, was at fault. Among them was former president Donald Trump, who often used inflammatory language to describe the virus's origins in China. But that notion was dismissed by Democrats and many scientists, who viewed the focus on the lab as part of a larger attack on China that fueled an increase in hate crimes against Asian Americans. "There was so much inaccurate information flowing from the White House that many viewed this as just another thing that was not true and a way for the White House to divert attention from a fledgling covid response," said Chris Meekins, a former Health and Human Services official who is now an analyst at Raymond James, a financial services firm. But in recent weeks, some notable researchers have begun arguing more pointedly that the lab theory should remain on the table until more is known, including some who made the case in an article in the journal Science. A series of reports in the Wall Street Journal, including one highlighting how several Wuhan lab employees became sick in fall 2019 with covid-like symptoms, have boosted the reexamination. The origin of the deadliest pandemic in recent memory carries enormous implications for public health — and beyond. If investigators point to China, one of the most powerful and sensitive countries in the world, it could ignite a global diplomatic firestorm. Health officials complain that China has hampered investigations into the matter, and a definitive finding could remain elusive despite Biden's directive.