Delta variant 'greatest threat' to US COVID-19 efforts, Dr Anthony Fauci warns at White House briefing

The Covid-19 delta variant, first identified in India, now accounts for more than 20 per cent of coronavirus infections in the US, the Centers for Disease Control and Prevention said on Tuesday.

"The delta variant is currently the greatest threat in the US to our attempt to eliminate Covid-19," Dr Anthony Fauci, the country's top infectious disease expert, warned at a White House briefing. "Good news: Our vaccines are effective against the delta variant."

The variant makes up more than 50 per cent of new infections in Iowa, Kansas, Missouri, Nebraska, Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming.

With the delta variant spreading rapidly among younger populations, Biden's White House is urging 18 to 26-year-olds to get vaccinated. Fauci lists under-vaccinated regions as the country's main "obstacles" to crushing the virus.

"If you look at the growing threat of what we're all concerned about: the Delta variant. What do we know about that variant? The transmissibility is unquestionably greater than the wild-type SARS-CoV-2, as well as the Alpha variant. It is associated with an increased disease severity, as reflected by hospitalization risk, compared to Alpha," Fauci said.

Fauci pointed to an Imperial College study of over 100,000 homes which found that youth were driving the UK surge. The results showed a fivefold higher positivity among children 5 to 12 and young adults 18 to 24, versus people older than 65 years old.

He then went on to list the "good news": vaccine effectiveness. "Two weeks after the second dose of Pfizer-BioNTech -- was 88 per cent effective against the Delta and 93 per cent effective against the Alpha when you're dealing with symptomatic disease," Fauci said.

Both the Pfizer-BioNTech and AstraZeneca shots have shown between 92 and 96 per cent effectiveness against hospitalizations.

"We have the tools, so let's use them and crush the outbreak," Fauci said.

At this time, the US is just short of vaccinating 70 per cent of all American adults with at least one shot by Independence Day - July 4. More than 150 million are fully vaccinated, as of Monday. Among those ages 30 and above, 70 per cent have at least one shot. For those over 40 years, 75 per cent have received at least one shot. Biden's Covid-19 response team thinks the country will hit the 70 per cent target for ages 27 and over once the data for the July 4th weekend is in.

US Covid-19 caseloads and deaths are at their lowest levels since the pandemic exploded here last year. The country is now averaging about 11,000 new infections and less than 300 deaths per day. The virus has so far killed more than 602,000 people in the US alone.