June 24, 2021 -- The Delta variant is infecting a growing number of people in the United States and has become the nation’s greatest threat in the effort to control COVID-19, White House medical advisor Anthony Fauci, MD, said Tuesday at a news briefing.
Fauci said the U.S. appears to be following a pattern set in the U.K. with the Alpha (B.1.1.7) variant, which was first detected in the U.K. last winter.
“We seem to be following the pattern with the Delta variant, with a doubling time of about two weeks,” Fauci said.
“Similar to the situation in the U.K., the Delta variant is currently the greatest threat in the U.S. to our attempt to eliminate COVID-19,” Fauci said.
The variant, officially designated as B.1.6176.2, was behind 1.2% of sequenced COVID-19 samples on May 8, 2.7% on May 22, 9.9% on June 5, and 20.6% by June 19, Fauci said, citing data from the U.S. Centers for Disease Control and Prevention.
The good news, Fauci said, is that vaccines now being used appear to be effective against the Delta variant.
He said the Pfizer/BioNTech vaccine showed 88% efficacy two weeks after the second dose against symptomatic disease related to the Delta variant.
He said a U.K. study found the Pfizer and the Oxford-AstraZeneca vaccines are 92-96% effective against hospitalizations related to the Delta variant. (The AstraZeneca vaccine is not authorized for use in the United States yet.)
Fauci said a troubling note is that the Delta variant is infecting a growing number of young people in the U.K.
A study by the Imperial College of London determined that “youth were driving the U.K. surge, with a fivefold higher positivity among children 5 to 12 and young adults 18 to 24, versus people older than 65 years old,” Fauci said.
Fauci and CDC Director Rochelle Walensky, MD, both made another appeal to Americans to get vaccinated.
“COVID-19 vaccines are available for everyone ages 12 and up,” Walensky said. “They are nearly 100 percent effective against severe disease and death, meaning nearly every death due to COVID-19 is particularly tragic because nearly every death, especially among adults, due to COVID-19 is, at this point, entirely preventable.”