The coronavirus variants: What you need to know

New variants of the coronavirus circulating globally appear to increase transmission and are being closely monitored by scientists.

Driving the news: The highly contagious variant B.1.1.7 originally detected in the U.K. could become the dominant strain in the U.S. by March if no measures are taken to control the spread of the virus, the Centers for Disease Control and Prevention said Friday.

Why it matters: Countries are being overwhelmed by surges in cases that have led to border closures, quarantines and more aggressive pushes for the public to get vaccinated....