New York was once the epicentre of America's disastrous response to the Covid pandemic, with the sound of ambulance sirens becoming the soundtrack to the city that never sleeps.
But New York faces a return to the confronting scenes of early 2020 with the city's healthcare system again under pressure after setting a new pandemic record for daily Covid cases on Friday (local time).
The state tallied 21,027 new Covid-19 cases, surpassing the previous record of 19,942 set in January, the governor announced.
With the positivity rate at nearly 8 per cent, local council member and chair of the city's health committee, Mark Levine, warned the city is facing a "perfect storm" a week out from Christmas.
"Positivity has doubled in past three days, something we've never seen before here in whole pandemic," he Tweeted Friday.
"Hospitalisations are also increasing rapidly.
"NYC is heading into a perfect storm."
In New York, just over 71 per cent of the population is fully vaccinated against Covid-19, according to government figures. While that's higher than the national average in the US, it is lower than what some experts say is required to truly achieve a herd immunity effect.
Recent research has also showed two shots of the Pfizer vaccine is less effective against the Omicron variant, with a booster shot required to restore a similar level of protection.
"GET BOOSTED NOW. Tidal wave of Omicron likely coming to a hospital near you soon," Dr Tom Frieden, former chief of the US Centers for Disease Control and Prevention, posted on social media.
Omicron 'a whole new animal': NYC mayor
Speaking to CNN on Thursday (local time) , NYC mayor Bill de Blasio called the Omicron variant "a whole new animal".
"We got to be honest about the fact that it's moving very fast and we have to move faster," he said.
While cases aren't the main concern, across the US, hospitalisations for Covid-19 have jumped 45 per cent over the last month, according to a Reuters tally.
Vaccine coverage has reduced severe outcomes in hospitals, but some experts worry of the debilitating symptoms of Long Covid as cases surge again.
In the midwest state of Ohio, National Guard troops have been deployed to assist already stretched healthcare workers.
Omicron's enhanced level of infectiousness means it could cause many additional deaths, the top US infectious disease expert Dr Anthony Fauci said overnight.
"When you have a larger number of people getting infected, the total amount of hospitalisations is going to be more. That's just simple math," he told CNBC.
Dr Fauci also said officials in the country were discussing whether to redefine what it means to be "fully vaccinated" to include booster shots.
Denmark the latest European nation to propose new closures to curb Omicron
Much of the northern hemisphere is facing an Omicron-plagued Christmas with European countries which had hoped to open after reaching the 80 per cent double dose mark having to reintroduce restrictions.
Denmark's government on Friday (local time) proposed new restrictions to curb the rapid spread of the new Omicron variant, saying it now accounted for a fifth of new daily coronavirus cases registered in the country, but shied away from instituting a full lockdown.
The new restrictions, which will need approval from parliament, include closing theatres, cinemas, entertainment parks and conference centres, as well as measures to limit large crowds in stores and shops just seven days before Christmas.
"In record time, the rules of the game have again been changed," Prime Minister Mette Frederiksen said at a news conference.
"This is not a complete closure of the society, as we saw last winter," Ms Frederiksen said. "Our aim is still to keep as much of society open as possible."
The government also proposed to ban the serving of alcohol after 10pm and urged residents to limit their social contact and to work from home. Face masks will be made mandatory in most public places.
Denmark had scrapped all Covid-related rules in August.
Germany, Ireland and Switzerland were all moving toward further restrictions, following the footsteps of France, which closed its borders this week to most non-resident Britons.
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