Fully vaccinated Americans can discard masks and the need for social distancing outdoors and in most indoors settings, the CDC said Thursday in a dramatic announcement after months of mostly cautious measures. The new guidelines announced by Dr. Rochelle Walensky, director of the Centers for Disease Control and Prevention, represent a major step toward a return to normalcy for a nation battered and at times divided by a pandemic that has lasted more than a year. "Anyone who is fully vaccinated can participate in indoor and outdoor activities, large or small, without wearing a mask or physical distancing,'' Walensky said. "If you are fully vaccinated, you can start doing the things that you had stopped doing because of the pandemic.''