SARAH MCCAMMON, HOST:
A new coronavirus variant is raising concern in the U.K. Some are calling it delta plus. There's worry that it could be more dangerous than the current version of delta circulating in the United States. To fill us in on what's known about this new mutant, we've brought in NPR's variant expert, global health correspondent Michaeleen Doucleff. Hey there, Michaeleen.
MICHAELEEN DOUCLEFF, BYLINE: Hi, Sarah.
MCCAMMON: OK. The name of the variant sounds a little scary, right? Delta plus - what does that mean? Is it related to delta, first of all?