US authorities have removed all destinations from the country's Do Not Travel list.
The US Centres for Disease Control and Prevention (CDC) has moved 89 countries from the Level 4 classification.
The designation will now only be used for special circumstances, including a dangerous spike in Covid-19 levels or the emergence of a new variant in a country.
Before Monday, nearly 90 destinations were categorised as "very high risk" by US authorities, including almost all of Europe, one of the most popular destinations for US travellers. Today, there are no countries in the designation.
Most former Level 4 nations are now ranked as Level 3 places, which means the CDC believes there is a "a high level of Covid-19" in the country. Included in this list are the UAE, the UK and several European destinations.
Travellers who are not fully vaccinated are still advised to “avoid travel” to these destinations, but the warning does not apply to fully vaccinated visitors.
Only 12 countries, including Sri Lanka and South Africa, are ranked as Level 2 — designating a moderate risk of the virus.
The lowest risk level assigned by the CDC is a Level 1 ranking, which means travellers can expect a low risk of Covid-19.
This list is populated mostly by African and Asian nations and includes Saudi Arabia, the Philippines, India and Pakistan.
The CDC says that Level 1, 2 and 3 classifications continue to be based on a 28-day incidence or case counts.
In its broader travel guidance, the authority has recommended avoiding all international travel until fully vaccinated.
The shake-up of travel recommendations from US authorities comes a day after a Florida judge ruled to overturn the US extension on wearing face masks when flying.
The White House has since announced that the masking order is not in effect, and that the Transportation Security Administration (TSA) would not enforce the federal mask mandate at this time.
US airlines drop face mask requirements on flights
Since the move, several US airlines have announced that they will no longer require passengers to wear face masks on flights.
American Airlines — the biggest airline in the US by passenger numbers — said “in accordance with the Transportation Security Administration no longer enforcing the federal face mask mandate, face masks will no longer be required for our customers and team members at US airports and on domestic flights “.
On Monday, Delta Airlines said that masks “are optional for all airport employees, crew members and customers inside US airports and on board all aircraft domestically, as well as on most international flights.”
Southwest echoed this sentiment, declaring that employees and customers “will be able to choose whether they would like to wear a mask on flights, at domestic airports, and at some international locations.”
Other airlines including Alaska and low-cost carrier Avelo, also advised passengers to choose whether or not they wanted to wear face masks on flights.
Reactions from the public have been mixed, with some people on social media welcoming the move and others questioning it.
Twitter user Adam Flannery responded to Avelo's announcement that face masks were now optional by saying he would never fly with the airline again.
Another Twitter user questioned whether they might be able to cancel their flight with no fee due to the change.
“The mandate was in place when I booked so I would like to go with an airline that’s going to protect its fliers and staff?” wrote Dwhat?
Other users lauded the idea that passengers now had a choice on whether to wear a mask on flights or not. User @Neeiick said he had been waiting for the mandate to be cancelled in order to book a flight.
Travellers may still need to wear masks when flying internationally, if the destination they are travelling to requires it.
Some US airports and airlines may also still require travellers to wear face masks when flying.