The CDC changed its mask guidance for vaccinated Americans. Other countries are taking different approaches.

In the United States, fully vaccinated individuals can now leave their masks behind when walking, jogging, biking or dining with friends outdoors, federal officials said Tuesday. Ditching a mask at small outdoor gatherings is also deemed safe, but the CDC still recommends masks for indoor activities.

More than 52% of eligible people in the United States have received at least one shot, and the Centers for Disease Control and Prevention guidance followed calls from public health experts to relax mask mandates outdoors, where transmission is less likely. But officials warned that crowded outdoor events - like sporting events and concerts - are still dangerous, so both vaccinated and unvaccinated attendees should keep their masks on.

Masks - and requirements to don them - have prompted debate around the world since the start of the pandemic. Widely accepted in some places, they have been protested or completely forgone in others. In the United States, federal guidelines have shifted over time, and individual states have imposed different requirements. Mask-wearing became highly politicized, complicating efforts to enforce usage. But in places like Hong Kong and Japan, face coverings were widely worn even before the pandemic, so everyday mask-wearing easily became routine.

Studies show that wearing masks is one of the most effective ways to reduce coronavirus transmission. Some public health experts argue that societal immunity isn't yet high enough to take them off - particularly since vaccines are not 100% effective and questions remain about whether vaccinated people can transmit the virus. Some experts suggest that wearing a mask even if vaccinated can send a powerful signal to unvaccinated individuals - such as children - to do the same.

Other countries where sizable portions of the population are vaccinated have taken different approaches. Here's a look at a few.

- Israel

With the majority of its population now fully vaccinated, Israelis are flocking to restaurants, bars and concerts. Life in Israel is beginning to resemble a pre-pandemic reality - as evidenced by the recent proliferation of bare Israeli faces.

Earlier this month, the Israeli government lifted a mask mandate that had been in place for more than a year. Israelis are no longer required to wear masks outdoors, though masks are still obligatory in indoor public places and the Health Ministry recommends that people continue to wear them outside and at large gatherings. In schools, kids still have to wear masks indoors but can shed them between classes, while eating, or during gym class, according to the Times of Israel.

New daily coronavirus infections, which peaked at around 10,000 per day, now hover in the 80s. But health officials have said the pandemic isn't over - and they're keeping an eye on new variants that could prove more resistant to vaccines.

Still, reflecting many Israelis' newfound optimism that the pandemic is almost behind them, Tel Aviv beachgoer Tzuriel Arviv told The Washington Post this month that he's beginning to let his guard down.

"We had all kinds of habits," Arviv said. "We would check ourselves, 'Do we have a mask?' Who ever imagined such a thing before? But now, we can forget it."

- The United Kingdom

Previously a global virus hot spot - and the place where a particularly infectious and deadly variant was first detected - the U.K. has seen covid cases drop substantially from a peak in January.

More than 33 million people have received at least one dose of the vaccine, according to the BBC. Nineteen percent are fully vaccinated - but since the government is now prioritizing distributing first jabs, it could be a while before the rest of the population catches up.

Mask rules and other virus-related restrictions vary across England, Scotland, Wales and Northern Ireland. In England, home of extensive debate over mask-wearing and an initially resistant government, face coverings became mandatory on public transportation in June and inside shops and supermarkets in July. A host of other indoor settings also joined the list. Violators can be fined, though enforcement has been spotty.

Northern Ireland has mandated face coverings in shops since August and banks, restaurants, cafes and certain offices since October - but in businesses where social distancing systems are in place, masks aren't required. Scotland's government puts it bluntly: "you need to wear a face covering even if you have been vaccinated." Masks must be worn in most indoor public and communal spaces there, and Scottish authorities recommend wearing face coverings outdoors where social distancing is tricky. Wales, meanwhile, still mandates that people over the age of 11 wear masks in all indoor public places.

As its vaccination campaign proceeds apace, the U.K. is rolling back restrictions in stages this spring. Public health conditions permitting, England aims to remove all legal limits on social contact by the end of June. But Health Secretary Matt Hancock has said that even when requirements lift, he hopes masks become the norm on public transport as a matter of "personal responsibility."

- The United Arab Emirates

As infections in Dubai spiked in April 2020, the U.A.E. imposed a mask mandate and fined violators around $800 for noncompliance. Face coverings are required in public places, public transportation or commercial centers, when walking in "high-density public areas" outside and in private transportation. They can be removed when driving alone or with family, eating or drinking at restaurants, exercising or undergoing certain medical and beauty treatments. Children under 6 and people with qualifying medical conditions are exempted from the mandate.

With a harsh lockdown and strict enforcement system, the Gulf country brought its first coronavirus wave under control by the summer. Dubai opened its doors to tourists from across the world late last year, marketing itself as a restriction-free holiday destination. The influx led to a surge of coronavirus infections in January, prompting a reimposition of some restrictions and adding urgency to the Emirates' aggressive vaccination campaign.

The U.A.E. has run one of the fastest vaccination campaigns in the world, and everyone in the country has been eligible for a vaccine since mid-March. But there has been some concern about the efficacy of the Chinese Sinopharm vaccine, a critical component of the U.A.E.'s vaccine drive. After a small number of people showed a weak antibody response after receiving two doses, some are being invited to receive a third booster shot.

For now, the mask mandate remains in place. But as the country races toward full vaccination, it appears the government may shift its focus to penalizing those who haven't received the shot. Saif Al Dhaheri, a spokesman for the U.A.E.'s National Emergency Crisis and Disaster Management Authority, said in a statement last week that "strict measures are being considered to restrict the movement of unvaccinated individuals" and to bar them from entering certain places and accessing some services.