Anthony Fauci
Anthony FauciReuters

The top US infectious disease official, Dr. Anthony Fauci, told President Joe Biden on Sunday it will take about two weeks to have definitive information on the new coronavirus variant, Omicron, Reuters reports.

Biden, returning to Washington following the Thanksgiving holiday weekend, was briefed in person by his coronavirus response team on Sunday afternoon.

Fauci told Biden he believes existing vaccines are likely to provide "a degree of protection against severe cases of COVID", and officials reiterated their recommendation for vaccinated Americans to get booster shots, according to a readout of the briefing.

Biden was due to update the public on the new variant and the US response on Monday, the White House said.

Omicron, which was first detected in Southern Africa, has now been confirmed in Australia, Belgium, Botswana, Britain, Denmark, Germany, Hong Kong, Israel, Italy, the Netherlands, France, South Africa, and in Canada.

While there were no cases of the new variant in the US as of Friday, according to the Centers for Disease Control and Prevention (CDC), Fauci told ABC News' "This Week" earlier on Sunday that the new variant would "inevitably" reach the United States.

The Omicron variant, also known as B.1.1.529, was first identified in South Africa last Tuesday, before being detected in several other southern African nations.

While the new strain has 32 mutations on the spike protein – the portion of the virus which is replicated by the COVID vaccine to induce an antibody response – it remains unclear if the mutations make the variant more transmissible, or whether the mutations could help it to evade vaccine-based immunity.

Professor Barry Schoub, an advisor to the South African government on issues relating to the pandemic, said on Sunday that the Pfizer-BioNTech vaccine likely will still offer protection from serious illness, even in the face of the Omicron variant.

Speaking to Reshet Bet radio, Prof. Schoub explained: "This is a brand-new variant, it's a variant which was detected only a few - actually, a week ago in fact - but in Botswana, which is a neighboring country, and South Africa."

"So it's a new variant, and what's worrying us about this variant is it's got many more mutations than any of the other variants. It's got over 30 mutations, and the worrying thing is that these mutations are in the what we call the spike protein. The spike protein is that protein on the surface of the virus which the virus needs to get into cells and then establish infection. And many of these mutations, the changes in the spike protein, we know from other variants are associated with first of all being more contagious, more transmissible, and also escaping from immunity.”

"We've never had anything like this in any of the variants. So it's a completely new variant unrelated to any of the other variants, it's on its own evolutionary branch, completely separate from the others."