(CNN) — Eight nations in southern Africa are listed at the CDC's highest travel risk level for Covid-19. The countries are under various travel bans worldwide because of the Omicron variant of the coronavirus.
The US Centers for Disease Control and Prevention placed seven of those nations at Level 4 (highest travel risk) on November 27, a day after President Joe Biden made his proclamation on the travel ban.
Those destinations are:
• South Africa
An eighth nation in that group -- Botswana -- had already been at a Level 4 travel warning since July 6.
Typically, the CDC places a destination at Level 4 when more than 500 cases per 100,000 residents are registered in the past 28 days. That's what happened to Germany and Denmark on the November 22 update.
However, the southern African nations were added to Level 4 and put on Biden's travel ban because of Omicron, not their case numbers.
"The travel restrictions were implemented due to concerns about the Omicron variant, and unknowns surrounding the variant," the CDC said in an email to CNN Travel on Monday afternoon. "There is enough evidence to act to restrict travel and slow the spread of the variant, while still learning more about the degree of threat posed by this variant."
The other CDC risk levels:
Level 1 is "low risk" with fewer than 50 new cases per 100,000 residents logged over the past 28 days.
Level 2 is "moderate risk" with 50 to 99 new cases per 100,000 residents in the past 28 days.
Level 3 is "high risk" with 100 to 500 cases per 100,000 residents in the past 28 days.
Before the news of the Omicron variant swept the world, Eswatini, Malawi, Mozambique, South Africa and Zimbabwe were at Level 1. Namibia was at Level 2, and Lesotho was at Level 3.
Those southern African nations were the only changes in the CDC's November 27 update prompted by Omicron. Because of the holiday period, the CDC said it did not have another update for Monday but will update its list later in the week.
ROSLAN RAHMAN/AFP/AFP/Getty Images
The eight destinations in southern Africa are hardly alone on Level 4. Before the Omicron alarm rang late last week, much of the Covid-19 focus had been on a surge of cases in Europe.
Some of the popular tourist destinations in Europe -- and elsewhere in the world -- still at Level 4 on Monday included:
• Costa Rica
• Czech Republic
In all, more than 80 destinations are now at Level 4.
A question on many of our minds: How should I be thinking about Omicron in terms of travel safety?
There's still a lot scientists don't yet know about the new coronavirus variant, but the best thing anyone can do right now is to get vaccinated, according to Dr. William Schaffner, a professor of infectious diseases at Vanderbilt University Medical Center.
Getting vaccinated is essential for two reasons, he said.
The first is the Delta variant. "That's the virus that's here, right now, in each and every community, spreading," Schaffner said. "But No. 2, and this has to do with Omicron, it is likely that our vaccines will provide at least partial protection. And partial protection is always better than no protection."
The other essential safety measure is still wearing a mask when you're out in public.
Schaffner's advice on traveling is largely the same as it was before the discovery of the new variant.
Make sure you're vaccinated, wear a mask, socially distance as much as possible while you're traveling and carefully consider what you're going to do when you get there, which likely puts you at greater risk than the journey itself.
The Level 3 category had five updates last week, with a big showing in the Caribbean. These five destinations moved to Level 3 on November 22:
• US Virgin Islands
The move was actually good news for all five destinations, which had been at Level 4. You can view the CDC's risk levels for global destinations on its travel recommendations page.
In its broader travel guidance, the CDC has recommended avoiding all international travel until you are fully vaccinated.
"Fully vaccinated travelers are less likely to get and spread Covid-19. However, international travel poses additional risks, and even fully vaccinated travelers might be at increased risk for getting and possibly spreading some Covid-19 variants," the agency said.
Top image: A surfer carries his board as he braves the cold waters of the ocean near Cape Town, South Africa. (Photo by Marco Longari/AFP via Getty Images)