The new advice adds to guidance issued in early March saying that fully vaccinated people may gather in small groups in private settings without masks or social distancing, and may visit with unvaccinated individuals from a single household as long as they are at low risk for developing severe disease if infected with the virus.
The recommendations issued Friday do not alter the C.D.C. travel guidelines for the unvaccinated. The agency continues to discourage non-essential domestic travel by those who are not fully immunized, saying that if they must travel, they should be tested for coronavirus infection one to three days before their trip and again three to five days after concluding their trip. Unvaccinated travelers should self-quarantine for seven to 10 days if they don’t get tested after a trip, the agency said.
The C.D.C.’s guidance does not change the fact that many countries, including those in the European Union, still block most Americans from coming. Some are starting to make exceptions for those who are vaccinated. 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.
Some destinations and cruise lines already have started requiring that travelers be fully vaccinated. The cruise line Royal Caribbean is requiring passengers and crew members 18 or older to be vaccinated in order to board its ships, as are Virgin Voyages, Crystal Cruises and others. These companies plan to restart cruise operations this spring and summer, pending guidance from the C.D.C.
For the moment, airlines are not requiring vaccinations for travel. But the idea has been much talked about in the industry.