Oct. 4 (UPI) -- The U.S. Centers for Disease Control and Prevention on Monday added six new destinations to its most severe level of travel warning.
The health agency designated Armenia, Austria, Barbados, Croatia, Latvia and New Caledonia as "Level 4: Very High" travel risks, indicating that Americans should not travel to these destinations unless they are fully vaccinated against COVID-19.
CDC criteria define "Level 4" countries as those reporting more than 500 cases per 100,000 residents in the past 28 days.
A total of eight locations were also downgraded from Level 4 to "Level 3: High" on Monday, including Argentina, France, Iceland, Lesotho, Morocco, Nepal, Portugal and South Africa.
Destinations designated as Level 3 threats have reported between 100 and 500 cases per 100,000 residents within the past 28 days.
Peru and the Caribbean island of Saint Barthelemy were downgraded from Level 3 to "Level 2: COVID-19 Moderate" indicating 50 to 99 COVID-19 cases per 100,000 residents in the past 28 days.
Broadly, the CDC recommends Americans get fully vaccinated before embarking on any kind of international travel, while noting that "even fully vaccinated travelers may be at risk for getting and spreading COVID-19 variants."