Bosnia and Herzegovina, Romania and Belarus have been deemed "very high" risk ...

(CNN) — Bosnia and Herzegovina, Romania and Belarus were deemed "very high" risk travel destinations on Tuesday by the US Centers for Disease Control and Prevention.

Saint Vincent and the Grenadines in the Caribbean also moved into the "Level 4: Very high level of Covid-19" category on the agency's regularly updated list of travel advisories.

All the destinations that moved to Level 4 this week were previously listed as "Level 3: Covid-19 High." The Level 3 category applies to destinations that have had between 100 and 500 cases per 100,000 residents in the past 28 days.

These are the destinations added to Level 4 on October 12:

• Belarus
• Bosnia and Herzegovina
• Romania
• Saint Vincent and the Grenadines

New Level 3 locations

Six destinations moved to Level 3 on October 12:

• Gabon
• South Korea
• Spain
• Czech Republic
• Faroe Islands
• Uganda

Spain's situation improved, according to CDC criteria, moving down from Level 4. The other five locations -- Gabon, South Korea, Czech Republic, the Faroe Islands and Uganda -- moved up from Level 2.

Destinations carrying the "Level 2: Covid-19 Moderate" designation have seen 50 to 99 Covid-19 cases per 100,000 residents in the past 28 days.

In "Level 1: Covid-19 Low" destinations, fewer than 50 new cases per 100,000 residents have been logged over the past 28 days.

"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: The deserted "Old Bridge" of Mostar in Bosnia and Herzegovina is seen from an empty restaurant terrace on May 8, 2020. (Photo by Elvis Barukcic/AFP via Getty Images)