Trevor Bedford, an epidemiologist at the Fred Hutchinson Cancer Research Center in Seattle, said in a Twitter thread on Thursday that a steady decline in U.S. coronavirus cases that has brought levels back to where they were in late October could be threatened by the "rapid take-off of B.1.1.7." He said there is evidence that the B.1.1.7 variant "will reach 50% frequency in the U.S. perhaps by late March."
[...]
"I'm not sure at this point how much of a spring B.1.1.7 wave to expect," he said.  

In the U.S., there were 1,523  cases of B.1.1.7 reported across 42 states as of Feb. 18, according to CDC data.
[...]
In Britain, new daily coronavirus case counts have been hovering at about 12,000 for the last week. Christina Pagel, who leads a team of researchers at University College London who apply mathematics to problems in health care, said the B.1.1.7 variant now makes up about 90% of new cases in Britain.
[...]
Simon Clarke, a professor in cellular microbiology at the University of Reading, said that in addition to the B.1.1.7 variant being more contagious there is an emerging body of evidence suggesting it could be more lethal, a possibility that was initially raised by British scientists before being downplayed. He said there is anecdotal evidence from hospitals, not confirmed by studies, that the B.1.1.7 variant could be harming more younger people. However, he cautioned it was too early to drawn firm conclusions.

New viruses continue to emerge that threaten people, crops, and farm animals. Viruses constantly evade our immune systems, and antiviral therapies and vaccination campaigns can be powerless against them. These unique characteristics of virus biology are a consequence of their tremendous evolutionary potential, which enables viruses to quickly adapt to any environmental challenge.