A months long Vanity Fair investigation, interviews with more than 40 people, and a review of hundreds of pages of U.S. government documents, including internal memos, meeting minutes, and email correspondence, found that conflicts of interest, stemming in part from large government grants supporting controversial virology research, hampered the U.S. investigation into COVID-19’s origin at every step. In one State Department meeting, officials seeking to demand transparency from the Chinese government say they were explicitly told by colleagues not to explore the Wuhan Institute of Virology’s gain-of-function research, because it would bring unwelcome attention to U.S. government funding of it. In an internal memo obtained by Vanity Fair, Thomas DiNanno, former acting assistant secretary of the State Department’s Bureau of Arms Control, Verification, and Compliance, wrote that staff from two bureaus, his own and the Bureau of International Security and Nonproliferation, “warned” leaders within his bureau “not to pursue an investigation into the origin of COVID-19” because it would “‘open a can of worms’ if it continued.” There are reasons to doubt the lab-leak hypothesis. There is a long, well-documented history of natural spillovers leading to outbreaks, even when the initial and intermediate host animals have remained a mystery for months and years, and some expert virologists say the supposed oddities of the SARS-CoV-2 sequence have been found in nature. But for most of the past year, the lab-leak scenario was treated not simply as unlikely or even inaccurate but as morally out-of-bounds. In late March, former Centers for Disease Control director Robert Redfield received death threats from fellow scientists after telling CNN that he believed COVID-19 had originated in a lab. “I was threatened and ostracized because I proposed another hypothesis,” Redfield told Vanity Fair. “I expected it from politicians. I didn’t expect it from science.”