The very contagious and possibly more harmful Delta variant of the coronavirus “probably” will become the dominant strain in the United States in the coming months, Rochelle Walensky, director of the Centers for Disease Control and Prevention, said Friday on "Good Morning America."
“It's more transmissible than the Alpha variant or U.K. variant that we have here. We saw that quickly become the dominant strain in a period of one or two months,” Walensky said. “I anticipate that is going to be what happens with the Delta strain here.”
Vaccines have been effective against the variant, which first appeared in India, but Walensky expressed concern that the virus could mutate and render vaccines less effective.
Research from Scotland released this week showed the variant was about twice as likely to hospitalize patients than the Alpha variant is. The variant has been dominant in Scotland since mid-May, now making up more than 75 percent of cases there.
British Prime Minister Boris Johnson delayed the end of England’s lockdown this week amid the spread of the Delta variant, which data has shown is between 40 and 80 percent more transmissible than previous strains.
Walensky told governors on Monday that the Delta variant makes up nearly 10 percent of U.S. cases in June, up from 2.7 percent in May. In the interview, Walensky urged people to get vaccinated.