U.S. health regulators announced on Tuesday that fully vaccinated people can safely engage in outdoor activities like hiking and walking without wearing masks but should continue to use face-coverings in public spaces where they are required.

The updated health advice comes as more than 50% of all adults in the United States have now received at least one jab of COVID-19 vaccine, according to the U.S. Centers for Disease Control and Prevention (CDC).

The CDC said “the release of these new guidelines is a first step at helping fully vaccinated Americans resume activities they had stopped doing because of the pandemic, while being mindful of the potential risk of transmitting the virus to other.”

Wearing face masks has been considered by experts as one of the most effective ways of controlling virus transmission. With most coronavirus transmission occurring indoors, and inoculations on the rise, the use of masks outdoors has been under public debate for weeks in Washington as U.S. citizens look to enjoy the benefits of being fully vaccinated.

New coronavirus infections have dropped 16% in the last week as the U.S. surpassed 140 million people having received at least one dose of authorized vaccines from Pfizer/BioNTech, Moderna or Johnson & Johnson’s one-dose vaccine.

This was the biggest percentage drop in weekly new infections since February, according to a Reuters analysis of state and county data.