(CNN) — The US Centers for Disease Control and Prevention added five new destinations to its "high" risk category for travelers on Monday.
The Central American country of Belize, the Bahamas archipelago in the North Atlantic, the mountainous British overseas island territory of Montserrat, the Caribbean island country of Saint Vincent and the Grenadines and the southern African country of Eswatini were all moved to Level 3, or "high" risk for Covid-19.
Four of the destinations were previously listed as Level 2, "moderate" risk: Bahamas, Belize, Eswatini and Saint Vincent and the Grenadines. Montserrat moved up two risk levels from Level 1 or "low" risk.
The Level 3 "high" risk category is now the top rung in terms of risk level. Level 2 is considered "moderate" risk, and Level 1 is "low" risk.
Level 4, previously the highest risk category, is now reserved only for special circumstances, such as extremely high case counts, emergence of a new variant of concern or health care infrastructure collapse. Under the new system, no destinations have been placed at Level 4 so far.
In total, the CDC moved up five destinations to the "high" risk column on Monday:
• Saint Vincent and the Grenadines
Overall, the past four weeks of advisories have seen little in the way of the dramatic shifts in status that characterized this past winter and early spring during the original Omicron variant surge.
The "Level 3: Covid-19 High" category now applies to countries that have had more than 100 cases per 100,000 residents in the past 28 days.
Much of Europe has been stubbornly lodged there with the summer travel season getting ever closer. As of May 23, the following popular European destinations were among those remaining at Level 3:
• The Netherlands
• United Kingdom
It's not just European favorites that find themselves at Level 3. Numerous notable travel destinations around the world are among those in the high risk category, including the following:
• Costa Rica
• South Korea
There were about 115 destinations at Level 3 on May 23. Level 3 locations now account for nearly half of the roughly 235 places monitored by the CDC.
The CDC advises that you get up-to-date with your Covid-19 vaccines before traveling to a Level 3 destination. Being "up-to-date" means you have had not only the full initial vaccinations but any boosters for which you're eligible.
Kuwaiti buildings are illuminated in the colors of the national flag on February 20, 2021. Kuwait is now "moderate" risk for Covid-19.
Yasser Al-Zayyat/AFP via Getty Images
Destinations carrying the "Level 2: Covid-19 Moderate" designation reported 50 to 100 Covid-19 cases per 100,000 residents in the past 28 days. Three places were moved to this level on Monday:
This was good news for Kuwait, which moved down from Level 3. Jamaica and Mongolia moved up one risk level from Level 1 or "low" risk. Fewer than 20 places were listed at Level 2 on Monday.
In its broader travel guidance, the CDC has recommended avoiding all international travel until you are fully vaccinated. If you're concerned about a travel-specific health situation not related to Covid-19, check here.
To be in "Level 1: Covid-19 Low," a destination must have had 49 or fewer new cases per 100,000 residents over the past 28 days. Just one destinations was added to the category on May 23: Egypt.
Egypt had been listed as "unknown."
Level 1 had nearly 55 entries as of Monday.
Finally, there are destinations the CDC has deemed to be of "unknown" risk because of a lack of information. Usually, but not always, these are small, remote places or places with ongoing warfare or unrest.
There was only one addition to this category on Monday: Mauritania, which previously had been at Level 1.
The CDC advises against travel to these places precisely because the risks are unknown. Others in this category include French Polynesia, the Azores, Cambodia and Tanzania.
A medical expert weighs in on risk levels
Transmission rates are just "one guidepost" for travelers' personal risk calculations, according to CNN Medical Analyst Dr. Leana Wen.
We've moved into "a phase in the pandemic where people need to make their own decisions based on their medical circumstances as well as their risk tolerance when it comes to contracting Covid-19," said Wen, who is an emergency physician and professor of health policy and management at the George Washington University Milken Institute School of Public Health.
There are other factors to weigh in addition to transmission rates, according to Wen.
"Another is what precautions are required and followed in the place that you're going and then the third is what are you planning to do once you're there.
"Are you planning to visit a lot of attractions and go to indoor bars? That's very different from you're going somewhere where you're planning to lie on the beach all day and not interact with anyone else. That's very different. Those are very different levels of risk."
Vaccination is the most significant safety factor for travel, since unvaccinated travelers are more likely to become ill and transmit Covid-19 to others, Wen said.
And it's also important to consider what you would do if you end up testing positive away from home. Where will you stay and how easy will it be to get a test to return home?