As Michiganders tucked into turkey or cheered football last week, a new coronavirus variant sent shudders through the science and health communities around the globe.

The World Health Organization Friday classified the omicron variant as a “variant of concern,” because of several mutations that may make it more transmissible than earlier COVID-19 variants. Still, experts say, it’s not yet time to panic.

There’s still “more that’s unknown than known” about omicron, said Dr. Anu Malani, infectious disease lead for COVID-19 response at Canton-based Saint Joseph Mercy Health System.

This much is clear: If it isn’t here already, omicron will be soon.

“It’s very likely that it’s already here in the U.S., and it’s just a matter of time before we sort of find it,” Malani said.

Here’s what we know — and what we don’t.

What is omicron?

The B.1.1.529 variant, known as omicron, was first reported to the World Health Organization last week after an increase in infections in South Africa coincided with the detection of the B.1.1.529 variant.

As of late Monday afternoon, Nov. 29, omicron had not yet been detected in the United States. The Michigan Department of Health and Human Services has “re-analyzed” some 31,000 samples from positive COVID tests, and found that none so far have matched the omicron variations, Lynn Sutfin, MDHHS spokesperson, told Bridge Michigan.

Will existing COVID vaccines work against omicron?

Experts, including Dr. Anthony Fauci — the White House’s chief adviser on COVID — said they are concerned that currently formulated vaccines may not provide the same protection against omicron, but it’s still unclear.

“We’re preparing to” update vaccines, “but we might not have to,” Fauci said Sunday, Nov. 28, on NBC’s Meet the Press.

Omicron has immediately “raised alarm bells” because of several mutations on its spike protein, said Adam Lauring, a virologist and infectious disease physician at the University of Michigan.

Spike proteins allow coronaviruses to attach to cells and climb inside to replicate. The three approved U.S. COVID vaccines — mRNA vaccines produced by Pfizer and Moderna, and the Johnson & Johnson version — are developed so the spike protein that appears after a person is exposed to the virus triggers an immune response. The resulting counterattack by antibodies blocks the spike proteins from binding to cells.

It’s not yet known whether the spike proteins in omicron will trigger the same immune response. Even if they do, it’s not yet clear whether the immune response will be enough to shut down the ability of the spike protein to breach cells, Lauring said.

On Nov. 29, President Joe Biden promised that — if a new vaccine is needed — the United States will “accelerate their development and deployment with every available tool.”

Pfizer and Moderna have both pledged to update their vaccines if needed. On Friday, Moderna noted in a statement that omicron’s “combination of mutations represents a significant potential risk to accelerate the waning of natural and vaccine-induced immunity” and said it’s already testing its current vaccine against the variant.

Pfizer CEO Albert Bourla said an update of its vaccine could be ready within 100 days.

How does omicron compare to delta?

That’s a crucial question.

It was delta that fueled the resurgence of COVID-19 cases after a hopeful case slump this summer. In fact, delta now makes up nearly every case in the United States, according to the Centers for Disease Control and Prevention.

“We’re going to want to know, does (omicron) spread faster than other viruses? Does it transmit better? If it can’t outcompete delta, delta might just crush it. That has happened. Delta just crowded out all the other viruses,” Lauring said.

Likewise, it’s not yet clear whether omicron causes more severe illness compared to other variants. Some of the first reports of omicron infections were found at universities, and younger individuals tend to have more mild disease.

Reinfection is another worry, since some of the first people who tested positive for the omicron variant previously had COVID-19, and it’s not clear how that compares to reinfections with other variants.

It could take months to answer the question about the severity of disease caused by this variant — which is really the bottomline concern, said Malani at Saint Joseph.

“What we don’t know — and this is going to take a little bit time to sort out — is what will be the impact on hospitalizations? What will be the impact on deaths?”

Will COVID tests detect omicron?

According to both the WHO and CDC, polymerase chain reaction, or PCR tests, usually done in a testing clinic or medical center, will detect infection with omicron.

It’s less clear how reliable other tests, including rapid antigen detection tests, will be in detecting omicron.

What about current treatments?

Corticosteroids and monoclonal antibodies have been effective for managing patients with severe COVID-19, but they will have to be continuously assessed to see if they are as effective against omicron.

How is international travel affected?

The United States has barred travel from South Africa and seven other southern African nations. More than 40 countries worldwide have imposed similar restrictions, while Japan and Israel are blocking all foreign nationals from entering their countries.

The CDC also issued an advisory to avoid travel to South Africa and, if you must travel, to be fully vaccinated before you go. “Because of the current situation in South Africa,” the advisory said, “even fully vaccinated travelers may be at risk for getting and spreading COVID-19 variants.” Some accounts of U.S. travelers stranded in South Africa are trickling in.

As of Nov. 29, the U.S.’s recently reopened border with Canada remains open, despite confirmation Sunday of the first two cases of the variant in Ontario. Canada’s health minister said that as testing and monitoring continues, “it is expected that other cases of this variant will be found.”

It remains unclear whether that could affect Michigan travel to and from Canada, though the border to Canada was closed to all but essential workers for more than 18 months following the pandemic’s initial outbreak in March 2020. Fully vaccinated U.S. residents were cleared to enter Canada in August.

Any change in the status of Michigan’s border with Canada is critical, as Michigan sees more than one million visitors from Canada in a typical year, a key cog in the state’s $26 billion tourist sector.

Biden said last week that while travel restrictions imposed on travelers from several southern African nations would slow the entry of the omicron variant, “it cannot prevent it.”

“Sooner or later, we’re going to see cases,” he said.

Bridge reached out to Detroit Metro Airport for reports of any impact from the travel ban, but did not hear back.

How omicron may affect Michigan health care?

If omicron proves to be more transmissible than the delta variant, that could add to the burden of Michigan hospitals already crowded with record numbers of COVID patients. Hospitals have reported high numbers of emergency room patients for more than two months, not only those with COVID but others who have put off care because of the pandemic.

John Karasinski, spokesperson for the Michigan Health & Hospital Association, an industry group, said in a statement its members are “closely monitoring” the variant, adding that it is premature to draw conclusions about its risk.

The statement added a plea for Michigan residents to follow safety guidelines including wearing masks and social distancing to help reduce the spread of COVID. “With how dire the situation is in our hospitals, we need the public’s help to slow the extreme growth of cases and hospitalizations,” the statement said.

Some Michigan hospitals near the border with Canada share another concern — a critical share of their workforce comes from across the border. Anything that interrupts that source of health care workers could be difficult to absorb.

At War Memorial Hospital in Sault Ste. Marie, CEO David Jahn said that upwards of 60 workers out of a workforce of 900 cross the border from Canada for their jobs. That includes about 15 nurses, a handful of physicians and four of the six pharmacists it employs.

“We couldn’t be able to staff our pharmacy if our Canadian employees weren’t able to come over the border,” Jahn said.

Like hospitals across Michigan, War Memorial is already up against a shortage of workers, as Jahn said: “About 25 percent of our positions are open. It’s across the board.”

As of now, Jahn said, “It’s more a situation of what-ifs. What if the border closed, even for essential workers? It would certainly have a significant impact for us.”

What should I do?

The WHO recommends countries step up surveillance and sequencing of COVID cases to better track the potential spread of omicron.

For individuals, the advice hasn’t changed in months: Don’t panic. Get vaccinated. Get a booster. The CDC has strengthened its booster recommendations, advising that all adults “should” get the booster; previously, the agency had recommended that adults “may” get a booster.

Mask up. And follow the same social protocols that have been advised for months — social distance, avoid poorly ventilated or crowded indoor spaces, open windows to improve ventilation, and stay home when sick.