WHO Says Delta Will Pick Off Most Vulnerable

Delta is now replacing alpha, the highly contagious variant that swept across Europe and later the U.S. earlier this year, Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia, said in a recent interview. And studies suggest it is around 60% more transmissible than alpha, which was more contagious than the original strain.

Delta has now spread to 92 countries, Maria Van Kerkhove, the WHO's technical lead for Covid, said Monday. It now makes up at least 10% of all new cases in the United States, according to the Centers for Disease Control and Prevention, and is on its way to becoming the dominant variant in the nation. And the United Kingdom recently also saw delta become the dominant strain there, surpassing its native alpha variant. The delta variant now makes up more than 60% of new cases in the U.K.