British Prime Minister Boris Johnson said on Monday he would take more steps to slow the spread of the Omicron coronavirus variant if needed, after the Netherlands began a fourth lockdown and as other European nations consider Christmas restrictions.

Speaking after UK media reported Britain might impose new curbs after Christmas, Johnson said the situation was “extremely difficult” and hospitalisations were rising steeply in London.

“I have to say to the British public, and I say to everybody, we will not exclude the possibility of going further if we have to do things to protect the public,” Johnson said after a cabinet meeting.

Omicron infections are multiplying rapidly across Europe and the United States, doubling every two or three days in London and elsewhere and taking a heavy toll on financial markets, which fear the impact on the global economic recovery.

The variant was first detected last month in southern Africa and Hong Kong and so far been reported in at least 89 countries. The severity of illness it causes remains unclear.

Read: How fast does it spread?: Scientists ask whether Omicron can outrun Delta

Any decision to limit how people can celebrate Christmas would come at a high political cost for Johnson, whose authority has been eroded by questions over whether he and his staff broke lockdown rules last year.

Asked about speculation that the government would ban indoor socialising and limit tourism, Johnson said: “I can certainly say we're looking at all kinds of things [...] to keep Omicron under control, and we will rule nothing out.”

Dutch Prime Minister Mark Rutte announced a shutdown on Saturday, ordering the closure of all but essential stores, as well as restaurants, hairdressers, gyms, museums and other public places from Sunday until at least Jan 14.

Germany plans to limit private gatherings from Dec 28 to a maximum of 10 people who have been vaccinated or recovered from Covid-19, according to a draft of proposed steps. The document also said access to restaurants would remain limited to people who could provide proof of vaccination or recovery.

Ireland on Friday ordered bars and restaurants to close at 8pm and reduced the capacity in all public events. Italy is also considering new measures, newspapers reported on Sunday.

Footfall and consumption

Coronavirus cases surged in New York City and around the United States over the weekend, dashing hopes for a more normal holiday season and stretching the country's testing infrastructure — just days before many families gather to celebrate Christmas.

In Washington DC, Mayor Muriel Bowser said the city would reinstate an indoor mask mandate beginning Tuesday and running until the morning of Jan 31.

All employees, contractors and grantees of the District of Columbia government must be fully Covid-19 vaccinated and have a booster shot, she said.

In Geneva, World Health Organisation chief Tedros Adhanom Ghebreyesus said the Omicron variant is spreading faster than the Delta strain and causing infections in people already vaccinated or who have recovered from Covid-19.

China must be more forthcoming with data and information related to the origin of the SARS-CoV-2 coronavirus, Tedros added.

“We need to continue until we know the origins, we need to push harder because we should learn from what happened this time in order to (do) better in the future.”

Wall Street's main indexes opened lower on Monday, dragged down by concerns about the impact of tighter Covid-19 curbs on the global economy. The Dow Jones Industrial Average fell 143.32 points, or 0.41 per cent, at the open to 35,222.12.

European stocks were down 1.33pc. Shopper numbers across Britain's high streets fell 2.6pc over the Dec 18-19 weekend versus the previous weekend, researcher Springboard said.

Last week, the European Central Bank cut its euro zone growth forecast for next year to 4.2pc from 4.6pc previously, citing the pandemic among “headwinds”.

ECB President Christine Lagarde said that, even if economies were learning to adapt to living with Covid-19, tighter restrictions could delay the recovery.

Gilles Moec, Axa Group chief economist, said in a note on Monday that a “mediocre” first quarter of 2022 was now possible across Europe and the United States.

Israel added the United States to its “no-fly” list, citing concerns over the Omicron variant. US infectious disease expert Anthony Fauci said Omicron was “raging through the world” as he urged Americans to get booster shots.

Since the start of this month, US Covid-19 cases have risen 50pc, according to a Reuters tally.

New York state recorded its third straight day of record cases with more than half in New York City, where Mayor Bill de Blasio called for the United States to “go on a war footing” to fight Omicron with vaccinations.

Booster shots, on top of two-shot vaccinations, appear key to fighting the variant. Moderna Inc said a booster dose of its vaccine seemed to be protective against Omicron in laboratory testing, and the current version of the shot would remain Moderna's “first line of defence”.

More than 274 million people have been reported to be infected by the coronavirus globally since the first cases were identified in China in December 2019. More than 5.65 million people have died.

The World Economic Forum on Monday postponed its annual meeting in Davos due to the spread of Omicron, putting off the event scheduled for January until mid-2022.