Delta variant the greatest threat to America's fight against Covid-19: Dr Anthony Fauci

Leading infectious disease expert and White House Chief Medical Advisor Dr Anthony Fauci on Tuesday named the highly contagious Delta variant of the coronavirus as the greatest threat to America's strive against the pandemic. He noted that the variant, first detected in India, is more contagious and causes more severe disease than other variants. Fauci was addressing a White House Covid-19 response team briefing.

The Delta variant forms over 20 per cent of all the cases in the US, double the 10 per cent two weeks ago. "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," Fauci said.

However, the head of the National Institutes of Allergy and Infectious Diseases (NIAID)added that US vaccines are effective against the variant. "Conclusion, we have the tools, so let's use them and crush the outbreak."

"The effectiveness of the vaccines, in this case, two weeks after the second dose of Pfizer BioNTech with 88 per cent effective against the Delta and 93 per cent effective against the Alpha when you are dealing with symptomatic disease," he asserted.

The Delta variant, which was deemed "a variant of concern" by the US Centers for Disease Control and Prevention last week, has surpassed the Alpha variant first discovered in the country. The strain makes up over 90 per cent of the new cases.

The transmissibility, disease severity and hospitalisation risk of the Delta variant are higher than the wild type SARS-CoV2 and the Alpha variant.

"Look at what is happening in the United States. We have seen, as was the case with B.1.1.7, we seem to be following the pattern with the Delta variant with a doubling time of about two weeks if you look from May 8 with 1.2 to 2.7 to 9.9 and as of a couple of days ago 20.6 percent of the isolates are Delta," Dr Fauci said.

"This is concerning but expected knowing what we do about how efficiently this variant spreads and by what we saw in the United Kingdom with this variant. We know our vaccines work against this variant; however, this variant represents a set of mutations that could lead to future mutations that evade our vaccine, and that is why it is more important than ever to get vaccinated now to stop the chain of infection, the chain of mutations that could lead to a more dangerous variant," Rochelle Paula Walensky, the director of the Centers for Disease Control and Prevention (CDC), said.

The CDC identified Delta as a VOC last week. "The B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.427 (Epsilon), B.1.429 (Epsilon), and B.1.617.2 (Delta) variants circulating in the United States are classified as variants of concern. To date, no variants of high consequence have been identified in the United States," the CDC said in a statement last week.

The World Health Organisation too classified the Delta variant as a variant of concern in May.