World stock markets advanced Thursday amid fading fears about both the Omicron coronavirus variant and elevated inflation.

Natural gas prices continued to fall sharply from record peaks struck earlier this week, but crude oil pushed upwards.

The upbeat pre-holiday mood was helped by two preliminary studies from Britain indicating Omicron infections were less likely to result in hospitalization compared with the Delta variant, confirming a trend first identified in South Africa.

The cautious optimism also got a lift from news the US Food and Drug Administration authorized Merck's Covid pill for high-risk adults, a day after green lighting a similar but more effective drug by Pfizer.

Another shot in the arm came after Britain's AstraZeneca revealed that the third, or booster, dose of its Covid-19 vaccine "significantly" lifted antibody levels against Omicron in a laboratory study.

New cases of the highly infections strain continued to soar, but market watchers are becoming more confident the health effects will be milder than with earlier variants, and have less impact on the economy.

The rebound from Monday's sharp sell-off "doesn't mean the market isn't concerned about Omicron," said Briefing.com market analyst Patrick J. O'Hare.

"But it does suggest the market isn't overly concerned about Omicron doing any extended economic damage."

On Wall Street, the S&P 500 concluded a shortened holiday week at a fresh record following a trove of mostly decent US economic data.

Commerce Department data showed consumer spending rose in November, thought at a slower rate, while inflation posted the biggest increase in nearly four decades which ate into income gains.

The hot housing market also continued to see price pressures amid a shortage of new homes available for buyers, while jobless benefit claims held steady from the prior week and orders for big-ticket manufactured goods climbed, though mostly due to aircraft.

Earlier, bourses in Europe and Asia also rose. Even a Covid lockdown in the Chinese city of Xi'an failed to dampen enthusiasm, with Shanghai closing 0.6 percent higher.

It was the last trading day before Christmas for Wall Street and the Frankfurt stock exchange, while London and Paris are open for half of a day on Friday.

New York - Dow: UP 0.5 percent at 35,950.56 (close)

US approval of Pfizer's anti-Covid pill and studies indicating Omicron infections were less likely to result in hospitalisation have cheered markets
US approval of Pfizer's anti-Covid pill and studies indicating Omicron infections were less likely to result in hospitalisation have cheered markets Pfizer via AFP / Handout

New York - S&P 500: UP 0.6 percent at 4,725.79 (close)

New York - Nasdaq: UP 0.8 percent at 15,653.37 (close)

London - FTSE 100: UP 0.4 percent at 7,373.34 (close)

Frankfurt - DAX: UP 1.0 percent at 15,756.31 (close)

Paris - CAC 40: UP 0.8 percent at 7,106.15 (close)

EURO STOXX 50: UP 1.2 percent at 4,266.97 (close)

Tokyo - Nikkei 225: UP 0.8 percent at 28,798.37 (close)

Hong Kong - Hang Seng Index: UP 0.4 percent at 23,193.64 (close)

Shanghai - Composite: UP 0.6 percent at 3,643.34 (close)

Euro/dollar: UP at $1.1337 from $1.1326 late on Wednesday

Pound/dollar: UP at $1.3409 from $1.3352

Euro/pound: DOWN at 84.46 pence from 84.83 pence

Dollar/yen: UP at 114.40 from 114.10 yen

Brent North Sea crude: UP 2.1 percent at $76.85 per barrel

West Texas Intermediate: UP 1.4 percent at $73.79 per barrel