Global travelers who've been vaccinated also don't need to take a COVID test before heading overseas, unless their destination country requires one, or self-quarantine upon arriving back in the US.
The new guidance comes as almost a third of the country's adult population has received at least one dose of a COVID-19 vaccine. "We are not recommending travel at this time, especially for unvaccinated individuals", Walensky said.
More than one in five adults in the United States is now fully vaccinated, CDC director Rochelle Walensky said at a briefing. "As of March 26, fully vaccinated Americans who can present proof of vaccination can visit Iceland, for example, and avoid border measures such as testing and quarantining, the country's government said", according to the report.
For travellers coming into the USA, vaccinated people should still get a negative COVID-19 test before boarding a flight, and be tested three to five days after arrival.
On Friday, the CDC announced that vaccinated Americans could travel safely in the nation without having to quarantine or get tested for COVID-19. Further, such people should also self-isolate at home for seven to 10 days after traveling. They do not need to quarantine.
White House COVID-19 adviser Andy Slavitt also asked Americans not to travel unless necessary. The agency noted the potential introduction of virus variants and differences in vaccine coverage around the world for the cautious guidance on overseas travel.
However, the agency still recommends that even fully vaccinated travelers wear a mask in public, and take other public health precautions, such as social distancing and avoiding crowds, and practicing hand hygiene.
The CDC cited recent research on the real-world effects of the vaccines for its updated guidance.
The report also noted that almost 1.6 million passengers boarded domestic flights on Sunday, which was the most on any day since the beginning of the coronavirus pandemic. Additionally, they can gather with unvaccinated people without masks, but the visits should be limited to one unvaccinated household at a time. That means the second shot for vaccines that require two jabs.
The U.S. began its vaccine rollout in mid-December.