The CDC announced in new guidance Thursday that anyone who is fully vaccinated can participate in indoor and outdoor activities without wearing a mask or physically distancing, regardless of crowd size.

What they're saying: "If you are fully vaccinated, you are protected, and you can start doing the things that you stopped doing because of the pandemic," CDC Director Rochelle Walensky will say at a White House press briefing.

Caveats: The guidance does not apply to those traveling on planes or public transit, health care settings, correctional facilities or homeless shelters.

• Masks should still be worn to abide by federal, state, local, tribal or territorial guidance, including local businesses and workplaces, the CDC said.
• Vaccinated people traveling from other countries to the U.S. still need a negative COVID test prior to their trip or proof of previous COVID infection in the past three months.

Between the lines: News reports this past week have pointed to public health experts' critiques of the agency's "overly cautious" guidance, which some say has not accounted for scientific findings that could change public attitudes and behaviors.

The CDC responded to the criticism Thursday, saying: "We have a responsibility to make recommendations based on a body of evidence and what the science tells us." The agency noted that it can now say with confidence:

1. The vaccines work in the real world
2. The vaccines stand up to the variants
3. Vaccinated people are less likely to transmit the virus

The bottom line: "We needed to take the time to review the full body of evidence to get this right, and that’s how we came to this decision," the CDC said.

The big picture: Cases have continued to fall dramatically, and deaths from the coronavirus are at their lowest level since last July.

• A majority of states have already entered a new phase in lifting mask mandates and other public health measures. Government officials have endorsed allowing individuals to assess their own personal risk of the virus.
• More studies have further confirmed the growing amount of evidence that vaccinated people are less likely to transmit the virus to others.

Go deeper: America is finally winning its fight against the coronavirus