4 questions scientists are racing to answer about the new Omicron coronavirus variant

• Dr. Anthony Fauci says we're about two weeks from having definitive data about the Omicron variant.
• We don't yet know whether Omicron spreads more easily or is more dangerous than Delta.

After a holiday weekend that began with frenzied headlines about a new coronavirus variant and ended with the White House reinstating COVID-19 travel bans, President Joe Biden attempted to reassure the American public during a Monday press briefing.

"This variant is a cause for concern, not a cause for panic," Biden said of B.1.1.529, which South Africa first reported to the World Health Organization on Wednesday.

The variant was dubbed Omicron and deemed a "variant of concern" by WHO, in part because preliminary evidence suggests it may increase the risk of reinfection with COVID-19.

But for now, that's about all experts know.

It will take roughly two weeks for scientists to produce definitive data on how easily Omicron spreads and whether it's more dangerous or deadly than past variants, Dr. Anthony Fauci, the top US infectious-disease doctor, told Biden during a Sunday briefing. Until we know more, Fauci stressed that booster shots for fully vaccinated Americans — and initial doses for the unvaccinated — were the best available protection against severe infection and death from COVID-19, including cases that originate from the Omicron variant.

In the meantime, here are the key questions scientists are racing to answer:

Is Omicron in the United States?

Probably.

While the Centers for Disease Control and Prevention had not detected any Omicron cases as of Friday, the US lags behind many nations in sequencing coronavirus samples.

"It's almost definitely here already," Dr. Scott Gottlieb, the former commissioner of the Food and Drug Administration, said during an interview with CBS News on Sunday. "Just looking at the number of cases coming off planes this weekend, it's almost a certainty that there have been cases that have gotten into the United States."

In addition to cases identified in South Africa and other countries in southern Africa, Omicron has been detected in the UK, Australia, Israel, and Hong Kong, among others.

"It's going to move around the world," Biden said during Monday's press briefing. "I think it's almost inevitable that there will at some point be that strain in the United States."

Is Omicron more transmissible than Delta?

It's unclear, but early evidence suggests it might be.

Omicron has more than 30 mutations on the virus' spike protein, which protrudes from the surface of the virus and which the vaccines teach our immune systems to recognize. By comparison, Delta, the dominant virus variant around the world, has 11 to 15 mutations on its spike protein, according to the CDC.

Omicron's constellation of mutations, coupled with its rapid spread in southern Africa, leads Nevan Krogan, a molecular biologist at the University of California at San Francisco, to believe Omicron spreads as easily as Delta does.

"There's a good chance that it's more transmissible," Krogan told Insider.

Sharon Peacock, who led the UK's genetic sequencing of the coronavirus at the University of Cambridge, seemed to agree. So far, the data suggests the new variant has mutations "consistent with enhanced transmissibility," she told the Associated Press, though "the significance of many of the mutations is still not known."

Is Omicron deadlier than previous variants?

Again, it's too soon to say.

While early anecdotal evidence out of South Africa suggests Omicron may produce mild disease, that picture is complicated by the fact that in South Africa, the new variant has been detected primarily in young people, who are less likely to develop severe disease from the virus in the first place, Krogan noted.

Those infections track with low vaccination rates among young people ages 18 to 34, only about a quarter of whom are vaccinated, according to Dr. Joe Phaahla, the country's health minister.

"The jury is still out in that regard," Krogan said of the virus' severity.

Can Omicron evade our vaccines?

Possibly.

In addition to mutations on the spike protein, Omicron has other mutations, a phenomenon that Krogan and his team have been studying for months.

"If we were going to draw the worst mutations we know on a board, this would be a perfect scenario," he said.

But while that might sound scary, it's actually a sign Krogan and his contemporaries in London, Paris, and New York have been on the right track with their research — and are already a step ahead of the game. They've been studying and anticipating combinations of nasty mutations on and off the spike protein for months.

On Monday, Krogan boarded a plane to New York to pore over data with fellow scientists and write up an attack plan against the new variant.

While more data is needed to say for sure whether protection from previous infection or vaccination will hold up against Omicron, Krogan's feeling is that the vaccines — and especially booster shots — will still continue to offer some protection.

"You get this big spike of antibodies that target spike proteins," he said of vaccination. Those antibodies may not be a perfect match for Omicron's many mutations, he added. "But quantity often trumps specificity," Krogan said.

Aria Bendix contributed to this report.