The stance by the Centers for Disease and Control Prevention (CDC) on face masks has taken many twists and turns throughout the COVID pandemic.

After initially claiming face coverings weren’t necessary, the CDC changed course in April 2020, calling on all Americans — even children as young as 2 years old — to mask up. 

That September, then-CDC Director Dr. Robert Redfield said during a Senate hearing that “face masks are the most important powerful health tool we have,” even suggesting that they might offer more protection than vaccines.

Those recommendations likely played a large part in 39 U.S. states eventually enacting mask mandates.

Now, a new scientific review — led by 12 researchers from esteemed universities around the world — suggests that widespread masking may have done little to nothing to curb the transmission of COVID-19.

Published by Cochrane Library, the review dug into the findings of 78 randomized controlled trials to determine whether “physical interventions” — including face masks and hand-washing — lessened the spread of respiratory viruses.