All about Omicron: What we know about the new COVID variant

Just as the world takes a breath from the Delta variant-induced third COVID surge that pushed hospitals past capacity this summer, a new variant—the omicron—is forcing countries around the world to once again consider shutting their doors.

It's too early to tell whether the variant will have the devastating effects of the Delta variant, the Mu variant—which accounted for 3% of U.S. cases before dropping off almost entirely by October—or somewhere in between. But as omicron continues to rise sharply in all provinces of South Africa, the Biden administration is reintroducing some travel restrictions that went into effect Monday.

As the variant spreads to countries around the world, including Canada, the Netherlands and Hong Kong, the World Health Organization declared omicron a "variant of concern"—though some are calling the move premature.

What is omicron?

The omicron variant, B.1.1.529, is now under strict watch from the WHO after quickly spreading throughout Southern Africa.

It's genetically different from the Alpha and Delta variants and has up to 30 mutations in its genetic code, leading some to worry that the risk of retransmission from those who have already had COVID could be high. The strain's mutations could also aid omicron in beating out other strains and spreading more quickly to hosts.

It appears to be doing the trick. While an Associated Press report found that case numbers in South Africa are still well below other pandemic peaks—3,220 new cases were reported in South Africa on Saturday— up to 90% of new cases in the South African province of Gauteng are omicron.

The strain's effects seem to be mild so far, and hospitals haven't been overburdened yet, though hospitalizations are rising.

And doctors worry that the full extent of the variant hasn't been realized. Vaccine hesitancy is strong among South Africa's youngest population—22% of those aged 18 to 34 are vaccinated—and most of those infected with COVID have been in those younger age groups. Doctors worry that older age groups will be more adversely affected.

And while experts in the country expected a fourth surge and possible variant, the omicron still came as a "shock" as it quickly spread to all nine South African provinces and other continents. It's now the first strain labeled as a "variant of concern" since the Delta variant.

It's unclear if the variant is more immune to vaccines, although some signs indicate that it's a possibility.

Where has it been detected?

The omicron strain still hasn't been detected in dozens of countries, and it's far from the first strain to make a mark since Delta. But it's coincided with a quick uptick in cases in South Africa, where it was originally found, and became the dominant strain in Pretoria, a city of around 750,000, in just a few weeks.

Omicron is now present in nearby Botswana and has jumped on board flights to Europe, Asia, Australia and North America. Hong Kong has detected three cases, while 10 European nations including the Netherlands, the United Kingdom, Portugal and Germany have found a total of 45 cases. Canada has detected three cases, and none have yet been found in the United States.

What has been done?

Against the wishes of both South Africa and the WHO, several countries have decided to once again shut their doors.

After detecting an omicron case, Israel decided to bar entry to foreigners, while Morocco suspended incoming international air travel for two weeks. Dozens of countries are restricting travel from Southern Africa to South Africa's chagrin—the government said travel restrictions are “akin to punishing South Africa for its advanced genomic sequencing and the ability to detect new variants quicker.”

The WHO also called for borders to remain open as closing borders appears to have a limited effect on the spread of variants, and many countries are hesitant to clamp down on restrictions that have limited its citizens for so long.

The United States said in a statement Friday that it would restrict travel from eight southern African countries except for citizens and permanent U.S. residents who test negative for the virus.

White House Chief Medical Adviser Dr. Anthony Fauci said Sunday that it's "too early to say" whether tightened COVID restrictions will be needed to combat omicron but that citizens must be ready to do “anything and everything” to prevent its spread.

When will we know more?

The WHO said it will take around two weeks to gauge the full effects of omicron, from its ability to evade vaccines to its contagiousness.

For now, countries have once again urged their citizens to get vaccinated. Some vaccine companies have already spoken about the strain, including Moderna, which said Sunday that a new vaccine that protects against the variant could be released in early 2022 if needed.

For now, Fauci said that the country must "prepare for the worst" just in case omicron becomes the culprit of yet another surge.

“Inevitably, it will be here. The question is will we be prepared for it? If and when, and it’s going to be when, it comes here hopefully we will be ready for it,” Fauci said.