The new coronavirus variant, Omicron, raises red flags among scientists — but there are more mysteries than answers about its public threat

• WHO labeled a new coronavirus variant, Omicron, a "variant of concern" on Friday.
• The B.1.1.529 variant contains signs of being more transmissible or dangerous than other strains.

A coronavirus variant first detected in South Africa has now spread to several other countries, including Israel and Belgium, prompting a spate of travel restrictions across Europe, Asia, and North America.

The new variant, called Omicron, carries a concerning number of mutations that could make it more transmissible or more likely to cause severe disease than the Delta variant, public-health experts say.

The World Health Organization labeled Omicron a "variant of concern" on Friday — a designation given to variants like Delta that require scrutiny from public-health officials. Preliminary evidence suggests that Omicron may increase the risk of reinfection relative to other variants of concern, WHO said.

But scientists have barely begun to examine Omicron's threat: Fewer than 100 of the variant's genome sequences have been reported globally, compared with Delta's more than 2.8 million sequences.

"We don't know very much about this variant yet," Maria van Kerkhove, WHO's technical lead on COVID-19, said at a Thursday briefing. "What we do know is that this variant has a large number of mutations, and the concern is that when you have so many mutations, it can have an impact on how the virus behaves."

She added: "It will take a few weeks for us to understand what impact this variant has."

Many scientists are hoping for answers much sooner than that, Katelyn Jetelina, an epidemiologist at UTHealth School of Public Health, told Insider. The variant could be lying undetected in some parts of the globe, she said.

"I would not be surprised if it's already landed in the US," Jetelina said. "We've already seen that this has been transmitting in communities like Turkey, Egypt, Belgium, Israel."

Omicron contains several new, unfamiliar mutations

South African researchers identified the first Omicron case on November 9, then reported the variant to WHO on Wednesday. Scientists are hopeful that they spotted the variant early, since the majority of known cases are still concentrated in southern Africa.

"South Africa has one of the best genomic surveillance systems in the world, so we know that they're really constantly evaluating this virus," Jetelina said. "For them to have 'only' detected 100 cases thus far in South Africa really gives us hope that this is the beginning stages of spread."

Still, a number of markers suggest that Omicron is highly transmissible relative to other coronavirus variants. For one, South Africa's coronavirus cases have risen sharply over the past few weeks: Average daily cases have risen thirteenfold since the variant was first discovered on November 9, from about 275 to 3,700 cases per day, according to Johns Hopkins University data.

Omicron also contains several worrisome mutations found in other variants of concern — including Delta and Alpha — that could help it spread, render vaccines less effective, or lead to more severe disease.

The new variant carries some unfamiliar mutations, as well.

"There are a number of mutations that we don't have any information about," Jetelina said. "They've never seen them on previous variants of concern. So, I think, one of the first questions is: What are these? Do we need to worry about them or not?"

So far, scientists have identified 32 mutations on the variant's spike protein — the protruding crownlike bumps on the surface of the virus that help it invade our cells. Other variants of concern have had fewer spike mutations.

"The spike protein is basically the key into our cells to infect us, so once that protein changes for better or for worse, then we need to really pay attention to it," Jetelina said. "That is probably what is creating this increase in cases that we're seeing in South Africa right now."

Public-health experts say there's no need for panic yet

A higher number of mutations doesn't necessarily make a variant deadlier or more transmissible — nor does it suggest on its own that Omicron will pose a greater challenge to vaccines than other variants of concern.

"We don't know yet if this new variant is outcompeting Delta," Jetelina said. "We also still don't know if it will evade our vaccines yet, either."

Scientists are still waiting on lab studies to determine how well coronavirus antibodies — either from natural infection or vaccines — hold up against Omicron. They're also watching carefully to see how quickly the variant spreads across the globe, particularly in countries with higher vaccination rates. (South Africa has fully vaccinated just 24% of its population, compared with 59% in the US.)

"We really just need to hold tight to see how this plays out and what our next move is," Jetelina said.

Moderna, BioNTech-Pfizer, and Johnson & Johnson all said on Friday that they were testing how well their vaccines protected against Omicron.

People who have been fully vaccinated and wear masks in public indoor settings shouldn't feel compelled to change their behavior right now, Jetelina added.

Mike Ryan, the executive director of WHO's health-emergencies program, shared a similar message on Thursday.

"Viruses evolve, and we pick up variations. It's not the end of the world. The sky is not falling in," he said. "There is this idea that we're just waiting for the next variant, and I don't want people to spend their lives worrying about that every day."