President Joe Biden on Monday said some US hospitals could be "overrun" by COVID-19 cases, but the country is generally well prepared to meet the latest surge and Americans need not panic.
In a virtual meeting hosted by the White House with several state governors and top health advisers, Mr Biden stressed that the rapid spread of the Omicron variant would not have the same impact as the initial outbreak of COVID-19 in 2020 or the Delta surge earlier this year.
"Omicron is a source of concern, but it should not be a source of panic," he said.
Testing is more widely available and mass vaccinations mean that for many people infections do not lead to serious illness.
"Because there have been so many vaccinations and boosters, we're not seeing hospitalisations rising as much as they did previously," Mr Biden said.
"Americans, America have made progress. Things are better."
But "with the rising cases, we still have tens of millions of unvaccinated people and we're seeing hospitalisations rise," he said. There are "hospitals in some places that are going to be overrun both in terms of equipment and staff".
Mr Biden acknowledged that despite surges in testing capacity, it's still not enough.
"Seeing how tough it was for some folks to get a test this weekend shows that we have more work to do," he said.
In addition to expanding free testing sites, the administration is pushing for more home testing kits, President Biden said.
"There were none when we took office. None. Now we have eight (brands) on the market," he said.
As part of the effort, the government is purchasing 500 million at-home tests for distribution to Americans.
"It's not enough. It's clearly not enough. If we'd known, we would have gone harder, quicker," he said. "We have to do more."
The US has suffered a pandemic toll higher than any nation, with more than 816,000 recorded COVID-19 deaths and 52 million cases.
Isolation changes
The US on Monday halved the isolation period for asymptomatic COVID-19 cases in a bid to blunt mass Omicron-induced disruption, as infections hit new highs in multiple US states and Europe, wreaking havoc on global air travel.
Some 11,500 flights have been scrapped worldwide since Friday and tens of thousands more delayed, during one of the year's busiest travel periods - with multiple airlines saying spikes in cases of the Omicron coronavirus variant have caused staffing shortages.
Effects rippled worldwide, with about 3,000 flights already cancelled on Monday and 1,100 more on Tuesday, according to flight tracker FlightAware.
Opening the way for more people to return to work sooner and minimising the prospect of mass labour shortages, the US Centers for Disease Control and Prevention on Monday cut isolation for asymptomatic COVID-19 cases from 10 to five days.
The guidelines, which are non-binding but closely followed by US businesses and policymakers, further suggest that the five-day isolation period be "followed by five days of wearing a mask when around others".
Cases in the US are already on track to reach record highs in January, fuelled by large pockets of unvaccinated residents as well as lack of access to quick and easy testing.
New measures in Europe
Governments worldwide are scrambling to boost vaccinations, stressing that the overwhelming majority of hospitalisations and deaths are occurring among the unvaccinated.
As several countries revive unpopular lockdowns, France stopped short of a stay-at-home order.
Ministers did call for employers to make staff work from home three days a week where possible after nationwide infections hit record-high figures - in line with Denmark and Iceland, which also reported record daily cases.
Similarly to the US, French Prime Minister Jean Castex said the government would announce by the end of the week a reduction in the number of isolation and quarantine days required for those with COVID-19 and their contacts.
England's Premier League, meanwhile, announced that a record 103 players and staff had tested positive in the past week.
And in Greece, authorities will require bars and restaurants to close at midnight from 3 January, when establishments will also have to limit the number of diners per table to six.
China strategy tested
In the Chinese city of Xi'an, authorities were scrambling to contain the country's worst COVID-19 outbreak in 21 months.
Desperate to keep a lid on the pandemic before February's Beijing Winter Olympics, China has stuck to a "zero-COVID" strategy, involving tight border restrictions, lengthy quarantines and targeted lockdowns. But there have been sporadic flare-ups.
Some 13 million residents are already confined to their homes in Xi'an, where COVID-19 controls were tightened on Monday to the "strictest" level, banning residents from driving.
Two other Chinese cities also reported a case linked to Xi'an, as authorities urged migrant workers not to travel home in the upcoming Lunar New Year holiday.
