The Delta variant now makes up more than 6 percent of SARS-CoV-2 infections in the US, CNBC reports, noting that this could be an undercount as the US only sequences a portion of cases. NPR adds that in some western US states it may account for about 18 percent of cases.
The variant, also known as B.1.617.2, was first identified in India and has since been found in 62 countries, CNBC says. In the UK, it has spread rapidly and now accounts for 60 percent of cases, outpacing the Alpha variant there, it adds. "We cannot let that happen in the United States," Anthony Fauci, the White House chief medical advisor, said during a press briefing on Tuesday, according to NPR.
Fauci added that the Delta variant appears to be more transmissible and may be associated with more severe disease, NPR reports, and that to combat it, the US must step up vaccinations. NPR adds that an analysis from Public Health England found that two doses of the Pfizer-BioNTech vaccine are 88 percent effective at protecting against symptomatic disease from Delta variant infection.