Anthony Fauci said the Delta variant of Covid-19 now represents about one in five new infections in the US, describing the new strain as the “greatest threat” to the country’s efforts to quash the pandemic.
Fauci, chief medical adviser to President Joe Biden, said during a press conference on Tuesday that the new strain, which was first discovered in India, had a “doubling time of about two weeks” in the US and was “following the pattern” of the Alpha strain, which was first identified in the UK, that became the dominant strain in the US during spring.
Fauci revealed that 20.6 per cent of genomically sequenced Covid-19 samples in the US in the two weeks ended June 19 were the Delta variant, up from 9.9 per cent a fortnight earlier and just 2.7 per cent of samples in the two weeks ended May 22.
“The transmissibility is unquestionably greater than the wild type and the Alpha variant,” he said, comparing Delta to the original strain of Covid-19 that originated in Wuhan and the variant that was first discovered last year in the UK, respectively.
Fauci referred to a study from Imperial College London that found young people were “driving the UK surge” of new Covid-19 infections there, and also said that the Delta variant was the dominant strain among sequenced samples.
“Similar to the situation in the UK, the Delta variant is currently the greatest threat in the US to our attempt to eliminate Covid-19,” he said.
The good news, he said, was that vaccines are effective against the new variant, with the BioNTech/Pfizer and Oxford/AstraZeneca jabs each more than 90 per cent effective at preventing hospital admissions against the Delta variant after two doses.
The most recent figures on the spread of the Delta variant in the US followed a concession from the White House earlier in the day that the country would miss Biden’s goal of having 70 per cent of American adults receive at least one dose of a vaccine by July 4. The current level is 65.4 per cent.