http://www.sciencemag.org/news/2021/02/coronavirus-strain-first-identified-california-may-be-more-infectious-and-cause-more

Masked pedestrians during a surge in coronavirus cases in the San Francisco Bay area in December 2020. A new study suggests a prevalent viral variant there may be more transmissible and lethal.

Science’s COVID-19 reporting is supported by the Heising-Simons Foundation.