Undetected cases, many of which were likely not severely symptomatic, were largely responsible for the rapid geographic spread of the COVID-19 outbreak in China, according to a new study. This scanning electron microscope image shows SARS-CoV-2 (round magenta objects) emerging from the surface of cells cultured in the lab. The virus shown was isolated from a patient in the U.S. Image credit: NIAID-RML. “The explosion of COVID-19 cases in China was...
