Harvard University associate professor Dr. Joseph Allen argued in favor of pulling back on masking children in schools, especially as U.S. drug regulators are set to authorize the Covid-19 vaccine to kids ages 5 to 11.

“We have to be careful that, if we don’t set firm deadlines, it’s easy to see how we can sleepwalk into indefinite masking,” said Allen during a Friday evening interview on CNBC’s “The News with Shepard Smith.” “With the approval of vaccines, expected very shortly, for 5 to 11-year-olds, it makes sense that we should no longer have mask mandates in schools.”

Allen also highlighted that while the Centers for Disease Control and Prevention has set metrics for masking for adults, the agency has “inexplicably” failed to set metrics on when kids can take away masks. 

The CDC did not immediately respond to CNBC’s request for comment. 

Allen echoed the guidance of Dr. Anthony Fauci, emphasizing that the best way to protect children was for adults to get vaccinated. 

“We should be mandating vaccines for all adults in schools,” said Allen.  

The director of the Healthy Buildings program at Harvard University’s T.H. Chan School of Public Health outlined additional methods to protect children in schools. They include expanding the use of rapid antigen tests and improving the ventilation and filtration systems in schools.