NEW: The CDC is updating its guidance on masks, saying that fully vaccinated people can be unmasked when exercising, socializing and dining outdoors in small groups. Can gather indoors with other fully vaccinated people without masks or distancing.

"Today is another day we can take a step back to the normalcy of before," CDC's Walensky says. "Over the past year we have spent a lot of time telling Americans what they cannot do ... Today, I'm going to tell you some of the things you can do if you are fully vaccinated."

Here are the CDC's new recommendations for when to wear a mask and when not to.