The agency recommended people avoid travel to Colombia, Costa Rica, Fiji, Guadeloupe, Jamaica, Kuwait, Mongolia, Niger, Peru, Romania, Saint Barthelemy, Saint Martin, Tunisia, the United Arab Emirates and the Dominican Republic.
Those who must travel to these places should make sure they are fully vaccinated against COVID-19 prior to their trip.
"Do not travel internationally until you are fully vaccinated," the advisory says. "Getting vaccinated is still the best way to protect yourself from severe disease, slow the spread of COVID-19 and reduce the number of new variants. CDC encourages you get a COVID-19 vaccine booster dose if you are eligible. People who are not fully vaccinated should follow additional recommendations before, during and after travel."
The CDC added that people should follow all airline requirements and any requirements at these destinations and that it recommended individuals get tested with a viral test one to three days before a trip.
Last week, the CDC added 22 countries and territories to the same list, including Albania, Argentina, Australia, Bahrain, Bermuda, Bolivia, Cape Verde, Egypt, Grenada, Guyana, Israel, Panama, Qatar, Saint Kitts and Nevis, Saint Lucia, São Tomé and Príncipe, Sint Maarten, Suriname, the Bahamas, the British Virgin Islands, the Turks and Caicos Islands and Uruguay.
Earlier this month, the agency also put Canada on that list.
Ten destinations were added to the "High" risk category on Monday, including Djibouti, Equatorial Guinea, Guatemala, India, Japan, Kosovo, Kyrgyzstan, Mali, Senegal and the Republic of the Congo.
Countries are designated as "Level 3" when between 100-500 cases per 100,000 residents are registered in the same timeframe.