<b>Live updates: follow the latest news on </b><a href="https://www.thenationalnews.com/coronavirus/2021/11/29/omicron-live-updates-covid-variant-vaccine-test-cases-travel/"><b>Covid-19 variant Omicron</b></a> America should prepare for the new Omicron coronavirus variant but the travel ban starting on Monday for most travellers from southern Africa should buy time to assess any new threat, US health authorities said on Sunday. "Inevitably, it will be here," although no cases have been detected yet, the nation's top infectious disease official, Dr Anthony Fauci, told ABC News. 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 and South Africa. US President Joe Biden, returning to Washington after the Thanksgiving holiday weekend, said he would meet his Covid-19 response team on Sunday afternoon and have more to say later. US health officials will also speak with those in South Africa on Sunday to get "more information in real time", Dr Fauci told NBC. He said the flight restrictions would give them more time to gather information and consider possible action. "It is to get us better prepared, to rev up on the vaccination, to be really ready for something that may not actually be a big deal but we want to make sure that we're prepared for the worst," Dr Fauci said. He said it was too early to know whether new lockdowns or mandates were needed. "It clearly is giving indication that it has the capability of transmitting rapidly," Dr Fauci said. "That's the thing that's causing us now to be concerned." Possibly more contagious than previous variants, Omicron has sparked worries worldwide and rattled markets. Its appearance in the US, where 30 per cent of the population has not had a single dose of vaccine, could undermine the nation's recovery nearly two years after Covid-19's emergence, and further pressure local medical systems already taxed by the Delta variant. Rising cases as colder weather forces more people indoors has also caused some hospital systems and US states, including New York, to declare emergencies. So far, nearly 782,000 people have died in the US from Covid-19 since early 2020, the most of any country in the world, amid more than 48 million infections, Reuters data show. Starting at midnight on Monday, the US will bar entry for almost all foreign nationals who have been in any of eight southern African countries in the past 14 days and has warned Americans against travelling to those nations. Flights by Delta Air Lines and United Airlines have continued from South Africa to the US since the variant was discovered. The Centres for Disease Control and Prevention did not immediately respond to a request for information about whether passengers from these flights were being screened. Dr Fauci and other top officials said the sudden burst of cases made Omicron worrisome and it remained unclear how current vaccines or treatments could be affected. "We need more data there before we can say confidently that this is not a severe version of the virus, but we should find that out in the next couple weeks," departing National Institutes of Health director Dr Francis Collins told Fox News. Vaccine makers Pfizer-BioNTech and Moderna say they expect more information soon. "We have to go through a couple of weeks yet of uncertainty," Moderna chief medical officer Dr Paul Burton told CNN. Dr Burton said Omicron's transmissibility and severity were also unknown, along with current vaccines' effectiveness against it. Dr Fauci pressed Americans to continue have Covid-19 vaccines and boosters while experts evaluate Omicron. "This is a clarion call: get vaccinated," he said. White House chief of staff Ron Klain echoed that sentiment, saying on Twitter: "The thing every vaccinated adult should do now, if they have not done it yet, is get a booster shot." The US has recorded more than 1.1 million new Covid-19 cases in the past 14 days, up 9 per cent from the prior two weeks, Reuters data shows. Michigan and Minnesota lead the nation in new cases, based on infections for every 100,000 residents. Arkansas Governor Asa Hutchinson expressed worry over another blow from the latest variant. "Delta has been tough on us," Mr Hutchinson told CNN. "And so we don't welcome a new variant and it is a great concern." The variant could cast a pall over the rest of the US holiday season and affect companies' plans for staff to return to offices. Banks and other companies have said they planned for workers to come back in January. On Wall Street, sources at major US banks and European banks with large American operations said they were not yet changing their policies but were monitoring the situation.