If everyone wore a mask, Covid-19 could be brought under control, CDC director urges

The two hair stylists in Springfield, Mo., broke the cardinal rule of infection control: Despite having respiratory symptoms, one went to work and saw clients for eight days, when she learned she had tested positive for Covid-19. Her colleague also developed symptoms, three days after her co-worker, and also kept working until she tested positive, two days after the first stylist. Together, they saw 139 clients, with appointments for haircuts, shaves, and perms lasting 15 to 45 minutes.

Yet when the local health department identified and contacted the 139 clients, asking them to self-quarantine for 14 days and checking in daily about whether they had developed Covid-19 symptoms, not a single one (of the 104 who agreed to be interviewed) did. Of the 67 who consented to a swab test, every one tested negative. There was one other notable fact about the case: Both stylists and every client had worn a face covering.

The stark case, described on Tuesday in Morbidity and Mortality Weekly Report, adds to the near-universal scientific consensus that, more than any of single action short of everyone entering solitary confinement, face coverings can prevent the transmission of the coronavirus that causes Covid-19.

“Like herd immunity with vaccines, the more individuals wear cloth face coverings in public places where they may be close together, the more the entire community is protected,” Robert Redfield, director of the Centers for Disease Control and Prevention, and two colleagues wrote in an editorial in the Journal of the American Medical Association, also published on Tuesday. Because cloth face coverings can also allow states to more safely ease stay-at-home orders and business closings, Redfield told a JAMA Live webcast Tuesday, “If we could get everybody to wear a mask right now, I really think in the next four, six, eight weeks, we could bring this epidemic under control.”

The “if,” of course, has been the problem. Because masking or refusing to mask has become a political statement, only 62% of Americans said in April that they did so (the CDC recommended the practice on April 3); in May, 76% said they did, according to another MMWR study. The CDC advice followed weeks of mixed and contradictory messaging, and even after it was issued, President Trump and other national leaders fell well short of endorsing face coverings.

Although mask wearing does not differ by gender, it does vary by region of the country. In May, 87% of people surveyed in the Northeast said they wore masks when going out in public; it was 80% in the West, 74% in the Midwest, and 71% in the South, where cases are skyrocketing.

Face coverings almost certainly explain why the Springfield hair stylists did not transmit the virus to a single client. Of the 104 clients surveyed, 102 said they wore a face covering (usually cloth coverings or surgical masks) during their entire appointment; two said they did for part of it. Both stylists were always masked.

The benefits of masking in reducing viral transmission are clear from much more than the unusual case of a Springfield hair salon, of course. In an unpublished analysis of 194 countries, those that did not recommend face masks saw per-capita Covid-19 mortality increase 54% every week after the first case appeared; in countries with masking policies, the weekly increase was only 8%.

And at the largest health care system in Massachusetts, Mass General Brigham, before administrators adopted a policy of universal masking for health care workers in late March, new Covid-19 infections in that population were increasing exponentially, from 0% to 21%, or 1.16% per day, on average, researchers reported in another JAMA paper published Tuesday. With everyone masked, the rate of Covid-19 in health care workers fell to 11.5% by late April, dropping 0.49% per day, on average.

In his editorial, Redfield made not only a public health case for face coverings but also an economic one. Citing an analysis by Goldman Sachs Research, he and his colleagues noted that if masking increased 15%, it “could prevent the need to bring back stay-at-home orders that would otherwise cost an estimated 5% of gross domestic product, or a projected cost of $1 trillion.”

“Broad adoption of cloth face coverings is a civic duty,” Redfield and his co-authors wrote in their editorial.