Centers for Disease Control and Prevention (CDC) has updated travel recommendations for four countries. CDC on Tuesday added Poland, Trinidad and Tobago, Niger, and Papua New Guinea to its ‘very high’ risk category of countries that travellers must avoid, even if fully vaccinated. The US government agency said if travelers “must” travel to these countries, they should be “fully vaccinated.” The four countries were moved to Level 4 due to an increase in their COVID-19 case count and concern over the Omicron strain of coronavirus that the World Health Organization has flagged as “variant of concern” with potentially high transmission and possibility of evading immunity provided by vaccines of previous infections .

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The four destinations, however, have not reported any cases of the Omicron variant which was first detected in South Africa in November and has triggered a slew of reinforced COVID-19 restrictions across the globe.

The CDC determines Level 4 “very high” destinations when they have more than 500 cases of the virus per 100,000 residents in the past 28 days.

There are over 75 countries listed as Level 4 “very high” risk for travel for Americans by the CDC based on COVID case count.

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While Poland, Trinidad and Tobago, Niger, and Papua New Guinea were moved up to Level 4, the CDC dropped another four destinations– Costa Rica, Bermuda, French Polynesia, and Guyana– from the category to Level 3 as their COVID situation improved.

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The CDC still recommends that travelers are fully vaccinated before traveling to these locations.

The CDC deems a destination as Level 3 or “high” risk when it has between 100 and 500 cases of the virus per 100,000 residents in the past 28 days.

Also receiving updated recommendations from the CDC were the British Virgin Islands and the Democratic Republic of the Congo, which dropped to Level 1 or “low” risk for travel.