Customers eat at the Reading Terminal Market in Philadelphia, Wednesday, Feb. 16, 2022. (AP Photo / Matt Rourke)

Centers for Disease Control and Prevention Director Dr. Rochelle Walensky said during a White House briefing that the government is contemplating a change to its mask guidance in the coming weeks.

Dr. Rochelle Walensky, Director of the Centers for Disease Control and Prevention (CDC) speaks during an interview with The Associated Press on Dec. 8, 2021, in Atlanta. (AP Photo / Brynn Anderson, File)

One year into Dr. Rochelle Walensky’s tenure as director, her bid to make the Centers for Disease Control and Prevention more agile is being challenged by political pressures, vocal scientists and the changing virus itself.

A doctor loads a dose of Pfizer COVID-19 vaccine into a syringe in a Dec. 2, 2021, file photo at a mobile vaccination clinic in Worcester, Mass. (AP Photo / Steven Senne, File)

The Centers for Disease Control and Prevention's advisers voted that a booster was safe for younger teens and should be offered to them once enough time — five months — has passed since their last shot.

(WTTW News)

Federal officials announced Monday a mass vaccination site will be opening in Gary, Indiana, as they warned of rising coronavirus cases across the country and urged residents to wear masks, social distance and limit travel.