In an updated guideline, the US Centers for Disease Control recommended that fully vaccinated people against Covid-19 can travel at low risk to themselves.
Fully vaccinated people can travel within the US, and Covid-19 testing or post-travel self-quarantine are not required as long as they continue to take precautions while travelling - wearing a mask, avoiding crowds, socially distancing, and washing hands frequently, Xinhua news agency quoted the CDC as saying on Friday.
The CDC defined fully vaccinated people as being fully vaccinated two weeks after receiving the last recommended dose of vaccine.
For international travel, fully vaccinated people do not need a Covid-19 test prior to travel, unless it is required by the destination, the CDC noted.
Meanwhile, fully vaccinated people do not need to self-quarantine after returning to the US.
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, according to the CDC.
The new guidance means that "fully vaccinated grandparents can fly to visit their healthy grandkids without getting a Covid-19 test, or self-quarantining, provided they follow the other recommended prevention measures", CDC director Rochelle Walensky said on Friday at a press briefing.
While fully vaccinated people may travel at low risk, Walensky said, "CDC is not recommending travel at this time due to the rising number of cases".
Recently the trends of the pandemic are changing in the US, as cases have increased during the past 12 days, CDC data show.
The current 7-day moving average of daily new cases stands at around 62,000 cases, an increase of 8.4 per cent compared with the previous 7 days, according to the CDC.
The US is still the worst-hit country with the world's highest number of cases and deaths at 30,606,649 and 554,069, respectively, according to the Johns Hopkins University.