Americans who are fully vaccinated can travel “at low risk to themselves,” both within the United States and internationally, but they must continue to take precautions like wearing a mask in public, avoiding crowds, maintaining social distancing and washing hands frequently, federal health officials said on Friday.

Vaccinated Americans do not need to get a coronavirus test before arriving in another country, unless required to do so by authorities at the destination, and they do not need to quarantine after returning to the United States unless required to do so by local jurisdictions, according to new recommendations from the Centers for Disease Control and Prevention.

But vaccinated travelers should have a negative result from a coronavirus test before boarding a flight back to the United States, and they should get tested against three to five days after their return home.