The variant, which was first identified in India and is also known as B.1.617.2, now accounts for 10% of cases in the U.S. and is spreading quickly. The variant led to a surge in cases in India and is prevalent across the U.K., which has led to a delay in reopening.
“It’s doubling every 2 weeks,” Scott Gottlieb, MD, a former FDA commissioner, said on CBS News’s Face the Nation on Sunday.
The delta variant is more transmissible than other strains and appears to remain contagious for longer periods of time, he said.
“That doesn’t mean that we’re going to see a sharp uptick in infections, but it does mean that this is going to take over,” he said. “And I think the risk is really … that this could spike a new epidemic heading into the fall.”
The Pfizer and Moderna vaccines appear to be about 88% effective against the delta variant after two shots, Gottlieb said. The Johnson & Johnson and AstraZeneca vaccines seem to be about 60% effective, but more studies are needed, according to USA Today.
Previously, the CDC classified the delta variant as a “variant of interest,” which means public health officials were cautiously watching its spread in the U.S. The “variant of concern” designation is given to virus strains that scientists believe are more prominent, more transmissible, or cause more severe disease, CNN reported. Tests, treatments, and vaccines may be less effective against these strains.
Last week, Anthony Fauci, MD, director of the National Institute of Allergy and Infectious Diseases, encouraged people to get vaccinated to protect against the delta variant. He said it is circulating in the U.S. and near the tipping point where it becomes the dominant strain in the U.K. On Monday, the U.K. delayed reopening by another 4 weeks, until July 19, due to an increase in COVID-19 cases and the spread of the delta variant.
“We cannot let that happen in the United States,” Fauci said during a White House COVID-19 briefing. “For those who have not been vaccinated yet, please get vaccinated.”
About 52.6% of the U.S. population has received at least one vaccine dose, according to the latest CDC tally updated on Tuesday, and 44% of the population is fully vaccinated. But the rate of vaccination has declined, particularly in Southern states, where less than a third of the population is vaccinated, CNN reported.
Picking up the pace of vaccination in the next few weeks is vital, Eric Topol, MD, director of the Scripps Research Translational Institute, told CNN. The institute runs the Outbreak.info website and has been tracking variants during the pandemic. The spread of the delta variant has become a major concern, he said.
“It doubles every 7 to 10 days, which means when it gets to 3 weeks from now, this variant will be dominant,” he said. “That means we have 2 to 3 weeks to just go flat out with vaccination to stop this trend.”