By Marie Saavedra and Asal Rezaei

CHICAGO (CBS) – The world is watching as a potentially dangerous new variant of COVID-19 has prompted the U.S. to lock down travel from South Africa and seven other African countries.

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The new restrictions begin Monday.

Meanwhile, a lot of doctors from whom we have heard in the past few weeks have said they expected COVID-19 numbers to rise as we get through this holiday season, and more people are gathering and traveling.

As CBS 2’s Asal Rezaei reported Friday night, one local doctor said with a spike in cases comes the possibility for the virus to continue its mutation – giving life to new variants.

Officials say it’s a decision made out of an abundance of caution, but the concern is real.

It was enough to send the Dow tumbling today more than 1,000 points. The S&P and NASDAQ both dropped over 2 percent.

The variant B.1.1.529 was found in South Africa. In the last eight hours, we’ve watched the world make changes because of it.

By Friday afternoon, The World Health Organization named it Omicron, calling it a variant of concern, due to a large number of mutations that carry an increased risk of re-infection.

Here at home, doctors say it’s worth being cautious.

“We’re not surprised a new variant has come up, this has been expected that we’re going to see new variants,” Dr. Rachel Rubin of the Cook County Department of Public Health told CBS 2’s Marie Saavedra.

Rubin said the risk of re-infection is indeed a concern.

“That indicates that quite possibly, we’re going to be seeing more breakthrough cases,” she said.

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The risk of breakthrough cases with the variant – as well as concerns about increased transmissibility – was enough for health officials to continue their push on getting vaccinated and keeping mask mandates in place.

It’s a lot of action to take for a still very mysterious strain.

“There’s no way of knowing if it’s here yet, though we will know soon, or if it’s going to become widespread,” Rubin said.

Dr. Rubin says research in the coming weeks will answer those questions.

In the meantime, the Delta variant continues to spread through Chicago. She says getting vaccinated or boosted puts up the best fight against that variant. Masking and distance should stay in place as we wait to learn more about the next one.

“That’s why these other things we do to keep ourselves safe apart from vaccines become that much more important,” Rubin said.

Dr. Anthony Fauci of the National Institute of Allergy and Infectious Disease, and the COVID Response Team, have been briefing President Joe Biden as information has come in.

“It’s in a fluid motion,” Fauci said. “We’re finding more about it and literally it’s something in real time. We’re learning more and more about.”

As they continue learning more, President Biden has ordered those air travel restrictions from South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi. The restrictions will not apply to American citizens and lawful permanent residents, who will still need to test negative for the coronavirus prior to travel.

Meanwhile, Dr. Rubin said the new variant will not be the last.

“We certainly know and expect that further variants will develop over time,” she said.

The race is also on to find out how well the current vaccines work against this new variant. Both Moderna and Pfizer say it will take a few weeks to know if its doses are effective against Omicron.

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And in his statement Friday, President Biden called on other countries to donate as many vaccines as the U.S. has. He also wants the intellectual property protections for COVID vaccines to be waved. If that happens, they can be manufactured globally and reach more people.

CBS 2 Chicago Staff