Even before the first case of COVID-19 was detected in the U.S., fears and uncertainties helped spur misinformation’s rapid spread. In March 2020, schools closed, employers sent staff to work from home and grocery stores called for social distancing to keep people safe. But little halted the flow of misleading claims that sent fact-checkers and public health officials into overdrive. Some people falsely asserted COVID-19’s symptoms were associated with 5G wireless technology. Faux cures and untested treatments populated social media and political discourse. Amid uncertainty about the virus’s origins, some even proclaimed COVID-19 didn’t exist at all. PolitiFact named downplay...