Coronavirus mutation has taken over the world. Scientists are trying to understand why.
When the first coronavirus cases in Chicago appeared in January, they bore the same genetic signatures as a germ that emerged in China weeks before.
Medical student Kimberly Olivares, left, takes a sample from a patient at a free COVID-19 testing site provided by United Memorial Medical Center at the Mexican Consulate, in Houston.Read moreDavid J. Phillip / AP
by Sarah Kaplan and Joel Achenbach, Washington Post
