In the days leading up to the pandemic declaration on March 11, national public health officials were saying people didn’t need to wear a mask, in some cases contending masks weren’t effective at preventing COVID-19 transmission.
But in April, the Centers for Disease Control and Prevention changed course and recommended that people wear a cloth face covering when distance from others could not be maintained.
The early advice was based on a lack of understanding about how COVID-19 spreads and the fear that a run on medical-grade masks would place health care workers in danger at a time when protective gear was in short supply.
But it soon became clear the virus was spreading via particles exhaled from the mouths and noses of infected people. And early experiments involving cloth face coverings suggested they could reduce the amount that escapes into the air. That, in turn, limits how much of the virus is inhaled by others nearby, which can prevent infection or reduce the severity of the disease.
“The truth was that we didn’t know how effective fabric masks were or were not, or are or are not. We know now,” said Dr. Emily Landon, executive medical director of infection prevention and control at University of Chicago Medicine.
Dr. Rahul Khare, CEO of the Innovative Express Care immediate care facility in Chicago and an early advocate of mask use, said he’s heartened that so many people have adopted mask-wearing in public.
“It has become a cultural norm to have a mask on when outdoors or when even in your office space, which three months ago would be crazy,” Khare said. “And we actually feel uncomfortable when we see someone or talk with someone who does not have a mask. So I think that’s pretty remarkable.”