Centers for Disease Control and Prevention Director Dr. Rochelle Walensky defended the agency’s Covid-19 mask guidance policies amid widespread criticism from lawmakers and health officials.  

“These issues are complex, the science is evolving, the science is moving, and we are following the science each and every day and our guidance is evolving as the science evolves,” said Walensky during a Wednesday interview on CNBC’s “The News with Shepard Smith.” 

Walensky pointed to the nation’s declining Covid cases and increasing vaccine rates. The U.S. positivity rate dropped to 3.1%, the lowest of the pandemic, according to Johns Hopkins University.  Nearly 59% of adults have received at least one vaccine, according to the CDC.  

The CDC chief also signaled to host Shepard Smith that guidelines will be changing soon, following the agency’s endorsement of administering Pfizer and BioNTech’s Covid-19 vaccine to adolescents aged 12 to 15.

“Today we have vaccines available, now for 12 to 15-year olds, [the agency’s guidelines are] going to have to evolve again, and I’m really enthusiastic about updating them very soon,” Walensky said.  

Smith also asked Walensky why, if everyone in his office was vaccinated, they still had to wear masks indoors. She explained that the CDC wants to ensure that the vaccines are working against all of the variants circulating in the U.S., and that “you’re not an asymptomatic carrier if you’re vaccinated” before completely doing away with masks in indoor settings.