For months, Americans have been told to wear a mask or cloth face covering in public settings. A face covering can prevent people who are asymptomatic carriers of Covid-19 from spreading the virus to other people.
But now new projections from the University of Cambridge illustrate how impactful the simple measure could be: Researchers found that that if 100% of people wore masks all the time in public, that, combined with lockdown measures, could prevent a second wave of Covid-19 from hitting during the 18 months that experts say it will take to get a vaccine to market.
The catch? There's no way everyone would comply. (More on that later.)
Luckily the study also projected that if at least 50% of people wore masks in public, that could still flatten the disease wave.
"We have little to lose from the widespread adoption of facemasks, but the gains could be significant," Renata Retkute, a doctor and coauthor and Cambridge team member, said in a press release.
But data shows that Americans, at least, are far from compliant.
According to a Gallup poll conducted in April, only 36% of Americans said they always wore a mask while out, with 32% reporting that they sometimes did and 31% saying they never did.
To put that in perspective, according to the theoretical models, face mask adoption by 25% of people could be enough to flatten the initial peak, but would still lead to a second wave Covid-19 that's more pronounced than the first.
A survey from YouGov of 89,347 American adults conducted between March 26 and April 29 found that people in certain states are more compliant than others when it comes to masks too. For example, in New York, 52% of people said they wore a mask when outside the home, while only 31% of Wisconsin residents reported using them.
Researchers used two models to determine the effect of different proportions — 0%, 25%, 50% and 100% — of people wearing masks for the Cambridge study.
And it's important to note that these findings are all theoretical. Since Covid-19 is a new disease, "it is impossible to get accurate experimental evidence" to use in a study, the authors wrote. The only way to run experiments is to use a mathematical model.
That said, experts agree that masks are still an important prevention measure, in addition to social distancing and hand hygiene.
White House advisor and immunologist Dr. Anthony Fauci told CNBC's "Halftime Report" that he has "no doubt" Americans who aren't wearing masks in public (especially in large gatherings) are increasing the risk of transmission.
"When we see [wearing masks] not happening, there is a concern that that may actually propagate the further spread of infection," he said.