BRUSSELS — The coronavirus’s omicron variant kept a jittery world off-kilter Wednesday as reports of infections linked to the mutant strain cropped up in more parts of the globe, and one official said that the wait for more information on its dangers felt like “an eternity.”

At the same time, the dominant delta variant continued to unsettle nations, especially in Europe, where many are still dealing with a surge in infections and hospitalizations and some are considering mandatory vaccinations.

Much is still unknown about omicron, including how contagious it is and whether it can evade vaccines. But governments have nevertheless rushed to impose restrictions they hoped would keep it out — moves that appeared increasingly futile, as Wednesday brought the first known cases in West Africa and the Gulf region. Showing an increasingly complicated web of contagion, Japan reported an omicron case in a man who came from Peru via Qatar.

“Scientists say the amount of mutations worries us,” said EU Commission President Ursula von der Leyen, and said it would take “two to three weeks” before it became fully clear what omicron could foist on the world.

“This is, in normal times, a short period. In pandemic times, it’s an eternity,” she said.

The worry and uncertainty about the new variant and the sometimes haphazard imposition of restrictions recalled the early days of the pandemic, as did the familiar realization that the virus had once again outpaced efforts to contain it.

South African researchers alerted the World Health Organization to omicron last week, but it is not known where or when the variant first emerged, though it’s clear it was circulating in Europe before that alert. Nigeria initially stretched that timeline back even further, saying it found the variant in samples collected in October — but it later corrected that to say the cases were detected in travelers who arrived in the country in the past week.

Regardless, the cases were the first reported in West Africa, while Saudi Arabia detected the first for a Gulf nation, a day after Brazil reported the first known one in Latin America.

Many countries around the world have barred travelers from southern Africa, and some have gone even further. Japan has banned foreign visitors and asked international airlines to stop taking new reservations for all flights arriving in the country until the end of December — among the most severe measures anywhere.

The U.S. is working toward requiring that all air travelers to the country be tested for COVID-19 within a day before boarding their flight. Currently those who are fully vaccinated may present a test taken within three days of boarding.

Leaders also continued to hammer home that the best way to contain the pandemic remains vaccinations.

For the first time, von der Leyen said that EU nations, should consider making vaccinations mandatory, like several have done for certain sectors, or like Austria, overall. In all, 67% of the EU’s population is vaccinated — but that relatively high rate hasn’t stopped several countries from seeing surges.

EU nations are taking different approaches now on pushing the shots. Starting in mid-January, Greece plans to impose 100-euro per month fines on people over 60 who don’t get vaccinated.

“The data is irrefutable: Nine out of 10 Greeks who lose their lives are over the age of 60 and more than eight out of 10 of the people (who die) are unvaccinated,” Greek Prime Minister Kyriakos Mitsotakis told parliament.

On the other hand, Slovakia is considering to give that age group 500 euros if they step forward for the shot. German chancellor-designate Olaf Scholz, meanwhile, said he will back a proposal to mandate coronavirus vaccinations for everybody next year.

Laurence Boone, chief economist at the Organization of Economic Cooperation and Development, pointed out that vaccination makes good economic sense too.

“The G20 countries have spent 10 trillion dollars supporting people and their economies since the beginning of the pandemic. It would only take 50 billion dollars to ensure vaccination worldwide,” Boone said. “I’m just saying.”

The world economy recovered faster than expected from the initial stage of the pandemic, but Boone warned it could all change quickly, especially since governments have often relaxed restrictions in a push to return to normalcy when the virus was far from contained.

“We are very concerned that many lessons have not been learned from recent experiences and the news about the omicron variant may actually be a reminder of how shortsighted that failure has been,” Boone said.

In the 27-nation EU, intensive care doctors are livid that politicians have not taken tougher action on mask use or ordered closures of restaurants, bars and leisure venues to make sure their units are not filled to overflow again.

Germany’s intensive care association warned Wednesday that the number of COVID-19 patients requiring intensive care will hit a new high before Christmas — and that it expected the all-time high from last year to be exceeded.

The DIVI association called for national restrictions to slow the spread immediately. German federal and state leaders are expected to decide Thursday on new measures to curb a sharp recent rise in coronavirus infections.

Austria, meanwhile, extended its lockdown until Dec. 11 as planned amid signs that the measures are helping to bring down a sky-high coronavirus infection rate there.

Germany and Austria are among several nations in Europe seeing surges — even some with high vaccination rates. Portugal — with an 88% vaccination rate that is among the highest globally — tightened entry requirements and mandated masks indoors Wednesday to slow an upward trend in. Until recently, the country was shielded from the spikes experienced by elsewhere on the continent.

South Korea, which is also seeing a delta-driven surge that has pushed hospitalizations and deaths to record highs, also extended a lockdown. The country on Wednesday reported a daily jump in coronavirus infections that exceeded 5,000 for the first time.