WASHINGTON — People who are fully vaccinated against COVID-19 can travel freely in the United States as long as they remain masked on planes, buses, and trains, the Centers for Disease Control and Prevention announced on Friday. For international travel, fully vaccinated people don"t need a Covid-19 test prior to travel — unless it is required by the destination — and do not need to self-quarantine after returning to the United States. They should still have a negative COVID-19 test before boarding a flight to the US, and a follow-up test three to five days after their return, the CDC noted. The CDC considers someone fully vaccinated two weeks after receiving the last required dose of the COVID-19 vaccine. The updated guidance does not apply to unvaccinated people. The CDC advises anyone who hasn"t been fully vaccinated to continue to avoid travel. Unvaccinated people who must travel should get tested one to three days before travel and again three to five days after travel. They should self-quarantine at home for seven days after travel, or 10 days if they do not get tested post-travel. The CDC said all Americans, regardless of vaccination status, should wear a mask and practice public health measures when traveling, such as physical distancing and washing hands frequently. During a White House briefing on Friday, Walensky said she continues to worry about the coronavirus pandemic — and with rising case numbers, she still recommends against nonessential travel. "We haven"t changed our guidance for nonessential travel at all. We are not recommending travel at this time, especially for unvaccinated people," Walensky said, emphasizing that the update is meant for those who are vaccinated — only about 20 percent of the adult population. "I still continue to worry that with 80 percent of the population unvaccinated that we still have a lot of work to do to control this pandemic," CDC Director Dr. Rochelle Walensky said. — Agencies