A new strain of COVID-19 initially seen in the United Kingdom has popped up in Colorado. The variant spreads quickly and has public health officials across the world worried.
Meanwhile, the vaccine rollout continues through the United States, though progress has been slow.
NPR science correspondent Joe Palca brings us the latest.
This article was originally published on WBUR.org.
Copyright 2020 NPR. To see more, visit https://www.npr.org.